Support passing a saltenv to slsutil.renderer

[ghost]

What does this PR do?

There is currently no way to use the module function slsutil.renderer for rendering files available on the salts fileserver, which are not available on the base environment, as the parameter for the saltenv is not passed to the method providing the file from the salt fileserver.

What issues does this PR fix or reference?

Not filed

Previous Behavior

salt '*' slsutil.renderer salt://path/to/file
salt '*' slsutil.renderer salt://path/to/file saltenv=banana

Both render salt://path/to/file from the base environment

New Behavior

salt '*' slsutil.renderer salt://path/to/file
salt '*' slsutil.renderer salt://path/to/file saltenv=banana

The first call renders the file salt://path/to/file available on the saltenv=base while the latter renders the file from the saltenv=banana

Tests written?

No

Commits signed with GPG?

Yes

[ghost]

What is needed to remove this forward?

[ghost]

@twangboy, what can I do to increase likelyhood of a merge approval? The last failing test looks like a new test issue (slack integration).

[max-arnold]

@waynew Could you please backport this PR to master branch?

[max-arnold]

Master backport: #55723