Added selection of preferred PowerShell version for Windows machines

[PiotrBaran1010]

Similar functionality as in #15 but with changes suggested by @froque

Reference: https://issues.jenkins-ci.org/browse/JENKINS-52421

[froque]

This a better PR than #15, but I'm afraid is still not what I was expecting.

With this PR I can choose PowerShell Version Preference between "Windows PowerShell" and "PowerShell Core" in global jenkins configuration (http://localhost:8080/jenkins/configure)

I was expecting to be able to configure each individual jenkins slave (http://localhost:8080/jenkins/computer/slave1/configure):

[PiotrBaran1010]

Would it be ok to have one global setting that the slaves would inherit by default, with the option to override it for individual slaves? I have a pretty complex setup in which slaves are created and removed dynamically based on load and I wouldn't want to modify settings per slave in that case.

[froque]

Would it be ok to have one global setting that the slaves would inherit by default, with the option to override it for individual slaves?

yes, that makes sense

[PiotrBaran1010]

Hi, @froque
Pushed new changes according to your suggestions, please check. Thanks!

[marcohald]

Is there anything new to this PR ?
I would also need this