components/zodbtools: reorganize test profiles

default profile no longer exist, now we have a combination of explicit
zodb versions and python versions:

{zodb4,zodb4-wc2,zodb5} x {py2,py3}

component/zodbtools/test-py2.cfg

+[python]
+part = python2.7

component/zodbtools/test-zodb4-py2.cfg

+# SlapOS software release to test zodbtools/ZODB4-py2 on Nexedi testing infrastructure.
+
+[buildout]
+extends =
+  test-zodb4.cfg
+  test-py2.cfg

component/zodbtools/test-zodb4-wc2-py2.cfg

+# SlapOS software release to test zodbtools/ZODB4-wc2-py2 on Nexedi testing infrastructure.
+
+[buildout]
+extends =
+  test-zodb4-wc2.cfg
+  test-py2.cfg

component/zodbtools/test-zodb4-wc2.cfg

-# SlapOS software release to test zodbtools/ZODB4-wc2 on Nexedi testing infrastructure.
+# SlapOS software release to test zodbtools/ZODB4-wc2-py3 on Nexedi testing infrastructure.
 
 [buildout]
 extends = test-common.cfg

component/zodbtools/test-zodb4.cfg

+# SlapOS software release to test zodbtools/ZODB4-py3 on Nexedi testing infrastructure.
+
+[buildout]
+extends = test-common.cfg
+
+[ZODB]
+major = 4

component/zodbtools/test-zodb5-py2.cfg

+# SlapOS software release to test zodbtools/ZODB5-py2 on Nexedi testing infrastructure.
+
+[buildout]
+extends =
+  test-zodb5.cfg
+  test-py2.cfg

component/zodbtools/test-zodb5.cfg

-# SlapOS software release to test zodbtools/ZODB5 on Nexedi testing infrastructure.
+# SlapOS software release to test zodbtools/ZODB5-py3 on Nexedi testing infrastructure.
 
 [buildout]
 extends = test-common.cfg

component/zodbtools/test.cfg

-# SlapOS software release to test zodbtools on Nexedi testing infrastructure.
-
-[buildout]
-extends = test-common.cfg