This was causing "No JSON object could be decoded"

now that promises are satisfied, we don't retry slapos node instance
again and again, so this test starts earlier and we need to wait longer
for ERP5 to be ready.

This test was just checking the data from the first recv call, but the
data might arrive in multiple times. Call recv in a loop until we
received the end of the expected message (or until timeout when
something goes wrong).

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 nexedi/slapos!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 nexedi/slapos!617

/reviewed-on nexedi/slapos!611