also drop test_nextcloud_promises as promises are now checked by
framework.

this seems to cause:
  Installing Computer Partition TestNextCloudParameters-0...
  Falling back to default buildout '/tmp/slaps/soft/8d7d1f38e7c55201a8be65b75e827d7b/bin/buildout'
  Uninstalling dynamic-template-lamp.
  Uninstalling slap-configuration.
  Installing slap-configuration.
  Installing dynamic-template-lamp.
  Installing switch_softwaretype.
  While:
    Installing.
    Getting section publish-connection-information.
    Initializing section publish-connection-information.
    Getting option publish-connection-information:monitor-setup-url.
    Getting section monitor-publish-parameters.
    Initializing section monitor-publish-parameters.
    Getting option monitor-publish-parameters:monitor-base-url.
    Getting section monitor-base.
    Initializing section monitor-base.
    Getting option monitor-base:base-url.
    Getting section monitor-conf-parameters.
    Initializing section monitor-conf-parameters.
    Getting option monitor-conf-parameters:base-url.
    Getting section monitor-instance-parameter.
    Initializing section monitor-instance-parameter.
    Getting option monitor-instance-parameter:monitor-base-url.
    Getting section monitor-frontend-promise.
    Initializing section monitor-frontend-promise.
    Getting option monitor-frontend-promise:config-url.
    Getting option monitor-frontend-promise:url.
    Getting section monitor-frontend.
    Initializing section monitor-frontend.
    Getting option monitor-frontend:config-url.
    Getting section monitor-httpd-conf-parameter.
    Initializing section monitor-httpd-conf-parameter.
    Getting option monitor-httpd-conf-parameter:htpasswd-file.
    Getting section httpd-monitor-htpasswd.
    Initializing section httpd-monitor-htpasswd.
    Getting option httpd-monitor-htpasswd:command.
    Getting option monitor-instance-parameter:password.
  Error: Referenced option does not exist: monitor-htpasswd passwd
  While:
    Installing switch_softwaretype

also drop test_turnserver_promises as promises are now checked by
framework.

slapos.cookbook:zero-knowledge.read has this limitation that because it
reads the secret file on __init__, ie. before any other parts are
installed, the value cannot be read the first time.
On first slapos node instance run, the generated turnserver-config has
an empty secret, it's only after the second execution that the secret is
generated. What happens is:
 - first run:
   - read-secret __init__ cannot find the file and does not override
     secret
   - turnserver-config uses the default ${read-secret:secret} (empty
     string)
   - gen-secret install creates the secret file
 - second run
   - read-secret __init__ finds the file and override secret with the
     value read from the file.
   - turnserver-config uses the overriden ${read-secret:secret} (good
     secret)

This was not a problem before, because some frontend promise were
always failing, so we processed this partition several time, but now it
is succesfully processed the first time.

To workadound this, we prevent turnserver from starting if secret is
empty, then promise will fail, instance will be processed a second time
and then turnserver will run with a secret.

This was causing "No JSON object could be decoded"

needed for slapos.testing

and make sure we really use the develop version, by clearing version pin
that might be for another version.

Also clean up comments in version section.

This will be needed for standalone tests.

Extract get-pip change in a separate commit
cc @jm @romain

/reviewed-on !621

Using WSGI became the default behavior in
f4d141a1.

--user=root is redundant and it will break with MariaDB 10.4

This is important for performance and it enables testless promises.

For partitions that are instantiated successfully, let slapos decide
when there's no parameter change (usually once a day).

Instantiation can be forced on manual action in the UI.

Remove method `generateHashFromFiles` in all file `test.py`, import it from `slapos.recipe.librecipe`.

/reviewed-on !617