This is a fixup of 9a886c4b

This way we don't need to vendor python-redis (so we don't need to
update it for python3 support).

This also change the options in a backward incompatible way:
 - options are now kebab case ( server_bin -> server-bin )
 - a new cli-bin option holding the full path to redis-cli command
 is required to enable promise

This allow to view captured image from the test result log url (snapshot directory).

This is a fixup of 9a886c4b

FIxup of e8220174fdfc386100a4927400d959c50d1be449

Also adapt build.sh for bootstrapping with python3.

This is a fixup of 4b28ab13. See also nexedi/slapos!1154

Instead of dropping some keys (easy to implement, impossible to test and easy
to leak) create whitelist of passed keys of slaves to the nodes.

Then if there are new keys in slave's connection parameters the nodes are
protected against being polluted with them.

Needed for `six` to avoid such message on:
  + from past.builtins import cmp
    => Redefining built-in 'cmp' (redefined-builtin)
  + from six.moves import xrange
    Redefining built-in 'xrange' (redefined-builtin)

Python2 already provides __code__ and __defaults__ so this just does the same on
PythonScript.

This default prevented extending the section with `inline` option
because `inline` and `url` conflict. This was not a problem when
the deprecated `template` or `template = inline:` option was used.

Setting `url = < nothing >` does not resolve the conflict currently.

Since all section that extend `jinja2-template` set their own `url`
or `inline`, the default value was never used anyway.

The default `filename` option is also no longer needed.

See merge request nexedi/slapos!1139

This software extends an old software, so we can not apply changes
that need a new version of slapos.recipe.template at this point.

By changing jinja2-template users from overriding url= to defining
template= the original url= option was expanded, but this failed
because there is no filename=. Define a default filename to prevent
this.

This fixes errors like for example:

    While:
      Installing.
      Getting section instance.cfg.
      Initializing section instance.cfg.
      Getting option instance.cfg:url.
    Error: Referenced option does not exist: instance.cfg filename

when installing component/pygolang/test.cfg

Revert "stack/ndtest,software/erp5testnode/testsuite: partially revert f5ebda78"

This reverts commit 90f29b1a and
subsequent fixups.

This partial revert was made in a rush without clear understanding
of the problem. Reverting the partial revert to apply proper fixes.

fixup! stack/ndtest,software/erp5testnode/testsuite: partially revert f5ebda78

fixup! stack/ndtest,software/erp5testnode/testsuite: partially revert f5ebda78

stack/ndtest,software/erp5testnode/testsuite: partially revert f5ebda78

These were actually :jinja2 versions of the recipe, so we can not
change them like this.

This commit was made in a rush to repair tests failing in loop, there
might still be mistakes.