Support powershell core

[twangboy]

What does this PR do?

Adds support for powershell core. The binary for powershell core is pwsh. Added tests.
Fixes running encoded powershell commands. This broke in Python 3, but we didn't know it. Added tests.
Moves a couple integration tests to pytest/functional

Powershell core is added to the golden image in this PR: saltstack/salt-ci-images#1688

When present, tests will run for pwsh binaries

What issues does this PR fix or reference?

Fixes: #58598

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltstack.com/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

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[s0undt3ch]

My only real concern are f-strings but, if Debian 9 and Ubuntu 16.04 don't choke, I'm cool with it.

[s0undt3ch]

Yep. Debian 9 choked. We can't, yet, use f-strings

[max-arnold]

Does it fix these issues?

#31351 (comment)
#31351 (comment)

[twangboy]

@max-arnold Yeah, I think so... I'll add some tests around your example

[twangboy]

@max-arnold Your first comment using cmd.powershell with encode_cmd=True works. I fixed the issue with the 2nd comment in the cmd.powershell function by prepending $ProgressPreference='SilentlyContinue' to the command before it is encoded.

With cmd.run and cmd.run_all however, that is impossible as the command is being passed to the function already encoded. So, I added some documentation about the need to prepend $ProgressPreference='SilentlyContinue' to the command before you encode it if you want to remove the raw xml data in the return.

As a note, this seems to only affect older versions of powershell. I don't get the raw xml data with Powershell Core, so maybe they've addressed that issue there.

[twangboy]

Not sure why Fedora 33 is failing... Everything else is passing