RFC: Make maintenance of Zope eggs versions by pulling them from upstream.

I don't see any reason why we don't use upstream zope *versions.cfg files. This
just duplicates work and makes maintenance tedious especially now that we have
zope2, zope4py2 and zope4py3.

Also:
  * Remove pinned versions on eggs with newer version or already defined in
    Zope versions.cfg files.
  * Make sure that pinned versions in stack/slapos.cfg do not override Zope versions
    (for example ZConfig versions set in stack/slapos.cfg was creating a version
    conflict while installing another egg).

stack/erp5/buildout.cfg

 [buildout]
-
 extends =
 # Exact version of Zope
-  ztk-versions.cfg
-  zope-versions.cfg
   buildout.hash.cfg
+# This has to be before Zope versions.cfg otherwise eggs such as ZConfig have
+# their versions overridden when slapos.cfg is extends by some component...
+  ../../stack/slapos.cfg
+  https://raw.githubusercontent.com/zopefoundation/Zope/4.5.3/versions.cfg
   ../../component/fonts/buildout.cfg
   ../../component/git/buildout.cfg
   ../../component/ghostscript/buildout.cfg
@@ -676,9 +677,7 @@ Zope = 4.5.3+SlapOSPatched002
 pylint = 1.4.4
 
 # use newer version than specified in ZTK
-PasteDeploy = 1.5.2
 argparse = 1.4.0
-zope.dottedname = 4.1.0
 
 # modified version that works fine for buildout installation
 SOAPpy = 0.12.0nxd001
@@ -719,7 +718,6 @@ WSGIUtils = 0.7
 astroid = 1.3.8
 erp5diff = 0.8.1.7
 five.formlib = 1.0.4
-five.localsitemanager = 2.0.5
 google-api-python-client = 1.6.1
 httplib2 = 0.10.3
 huBarcode = 1.0.0
@@ -761,8 +759,6 @@ zbarlight = 2.3
 cloudpickle = 0.5.3
 dask = 0.18.1
 toolz = 0.9.0
-zope.globalrequest = 1.5
-waitress = 1.4.4
 xlrd = 1.1.0
 
 # Re-add for as it is required to be there for uninstallation
@@ -791,20 +787,12 @@ jedi = 0.15.1
 parso = 0.5.1
 yapf = 0.28.0
 z3c.etestbrowser = 3.0.1
-zope.testbrowser = 5.5.1
-WSGIProxy2 = 0.4.6
-WebTest = 2.0.33
-beautifulsoup4 = 4.8.2
-WebOb = 1.8.5
-soupsieve = 1.9.5
 eggtestinfo = 0.3
 
 oic = 0.15.1
 Beaker = 1.11.0
 Mako = 1.1.4
 pyjwkest = 1.4.2
-alabaster = 0.7.12
-future = 0.18.2
 pycryptodomex = 3.10.1
 
 strict-rfc3339 = 0.7
@@ -814,8 +802,6 @@ jsonpointer = 2.2
 
 
 # WIP Zope 4 ⚠
-zope.interface = 5.2.0 
-ZConfig = 3.5.0
 Products.CMFCore = 2.4.0
 Products.StandardCacheManagers = 4.1.0
 Products.ZSQLMethods = 3.14

stack/erp5/zope-versions.cfg

-[versions]
-#Zope = 4.5.3
-Zope2 = 4.0
-# AccessControl 5+ no longer supports Zope 4.
-AccessControl = 4.2
-Acquisition = 4.7
-AuthEncoding = 4.2
-BTrees = 4.7.2
-Chameleon = 3.8.1
-DateTime = 4.3
-# DocumentTemplate 4+ no longer supports Zope 4.
-DocumentTemplate = 3.4
-ExtensionClass = 4.5.0
-Missing = 4.1
-MultiMapping = 4.1
-Paste = 3.5.0
-PasteDeploy = 2.1.1
-Persistence = 3.0
-Products.BTreeFolder2 = 4.2
-# ZCatalog 6+ no longer supports Zope 4.
-Products.ZCatalog = 5.2
-Record = 3.5
-RestrictedPython = 5.1
-WSGIProxy2 = 0.4.6
-WebOb = 1.8.6
-WebTest = 2.0.35
-ZConfig = 3.5.0
-ZEO = 5.2.2
-ZODB = 5.6.0
-ZServer = 4.0.2
-five.globalrequest = 99.1
-five.localsitemanager = 3.2.2
-funcsigs = 1.0.2
-future = 0.18.2
-ipaddress = 1.0.23
-# mock 4.0 and up requires Python 3
-mock = 3.0.5
-pbr = 5.5.1
-persistent = 4.6.4
-pytz = 2020.4
-roman = 3.3
-shutilwhich = 1.1.0
-six = 1.15.0
-transaction = 3.0.0
-waitress = 1.4.4
-z3c.pt = 3.3.0
-zExceptions = 4.1
-zc.lockfile = 2.0
-zdaemon = 4.3
-zodbpickle = 2.0.0
-zope.annotation = 4.7.0
-zope.browser = 2.3
-zope.browsermenu = 4.4
-zope.browserpage = 4.4.0
-zope.browserresource = 4.4
-zope.cachedescriptors = 4.3.1
-zope.component = 4.6.2
-zope.componentvocabulary = 2.2.0
-zope.configuration = 4.4.0
-zope.container = 4.4.0
-zope.contentprovider = 4.2.1
-zope.contenttype = 4.5.0
-zope.datetime = 4.2.0
-zope.deferredimport = 4.3.1
-zope.deprecation = 4.4.0
-zope.dottedname = 4.3
-zope.event = 4.5.0
-zope.exceptions = 4.4
-zope.filerepresentation = 5.0.0
-zope.formlib = 4.7.1
-zope.globalrequest = 1.5
-zope.hookable = 5.0.1
-zope.i18n = 4.7.0
-zope.i18nmessageid = 5.0.1
-zope.interface = 5.2.0
-zope.lifecycleevent = 4.3.0
-zope.location = 4.2
-zope.pagetemplate = 4.5.0
-zope.processlifetime = 2.3.0
-zope.proxy = 4.3.5
-zope.ptresource = 4.2.0
-zope.publisher = 5.2.1
-zope.ramcache = 2.3
-zope.schema = 6.0.0
-zope.security = 5.1.1
-zope.sendmail = 5.1
-zope.sequencesort = 4.1.2
-zope.site = 4.4.0
-zope.size = 4.3
-zope.structuredtext = 4.3
-zope.tal = 4.4
-zope.tales = 5.1
-zope.testbrowser = 5.5.1
-# Version 4.8+ dropped support for Python 3.5
-zope.testing = 4.7
-zope.testrunner = 5.2
-zope.traversing = 4.4.1
-zope.viewlet = 4.2.1

stack/erp5/ztk-versions.cfg

-[buildout]
-extends =
-    zope-versions.cfg
-versions = versions
-
-[versions]
-# Version pins for development and optional dependencies.
-Babel = 2.8.1
-Jinja2 = 2.11.2
-MarkupSafe = 1.1.1
-# Pygments 2.6.0 and up require Python 3
-Pygments = 2.5.2
-# Version 2.0+ needs Python 3.x
-Sphinx = 1.8.5
-alabaster = 0.7.12
-appdirs = 1.4.4
-attrs = 20.3.0
-backports.functools-lru-cache = 1.6.1
-beautifulsoup4 = 4.9.3
-bleach = 3.2.1
-buildout.wheel = 0.2.0
-# Version 2020.4.5.2 and up claim no Python 2 support
-certifi = 2020.4.5.1
-cffi = 1.14.3
-chardet = 3.0.4
-cmarkgfm = 0.4.2
-collective.recipe.cmd = 0.11
-collective.recipe.sphinxbuilder = 1.1
-collective.recipe.template = 2.1
-colorama = 0.4.4
-# configparser 5 and up require Python 3
-configparser = 4.0.2
-contextlib2 = 0.6.0.post1
-coverage = 5.3
-distlib = 0.3.1
-docutils = 0.16
-filelock = 3.0.12
-idna = 2.10
-imagesize = 1.2.0
-# tox and pluggy require importlib-metadata <1
-importlib-metadata = 0.23
-lxml = 4.6.1
-manuel = 1.10.1
-# Version 6+ needs Python 3.x
-more-itertools = 5.0.0
-mr.developer = 2.0.1
-nose = 1.3.7
-packaging = 20.4
-pathlib2 = 2.3.5
-pip = 20.2.4
-pkginfo = 1.6.1
-plone.recipe.command = 1.1
-pluggy = 0.13.1
-py = 1.9.0
-pycparser = 2.20
-pyparsing = 2.4.7
-python-gettext = 4.0
-readme-renderer = 28.0
-repoze.sphinx.autointerface = 0.8
-requests = 2.25.0
-requests-toolbelt = 0.9.1
-scandir = 1.10.0
-snowballstemmer = 2.0.0
-# soupsieve 2 needs Python 3
-soupsieve = 1.9.6
-sphinx-rtd-theme = 0.5.0
-sphinxcontrib-serializinghtml = 1.1.4
-sphinxcontrib-websupport = 1.2.4
-# tempstorage is only needed because the Sphinx documentation parses
-# ZConfig xml configurations, which still contain references to it
-tempstorage = 5.1
-toml = 0.10.2
-tox = 3.20.1
-tqdm = 4.51.0
-# Version 2+ needs Python 3.x
-twine = 1.15.0
-typing = 3.7.4.3
-urllib3 = 1.26.1
-virtualenv = 20.1.0
-webencodings = 0.5.1
-wheel = 0.35.1
-z3c.checkversions = 1.2
-zc.recipe.egg = 2.0.7
-zc.recipe.testrunner = 2.1
-zest.releaser = 6.22.1
-# Version 2 requires Python 3
-zipp = 1.1.1
-zodbupdate = 1.5