Leverage PowerShellBuild + Migrate to Pester 5 Tests

[HeyItsGilbert]

I tried (and failed) at keeping this small. My goal was to migrate to a cleaner build process so that future developers would have an easier time building and testing. With the build improved, this meant that publishing also became trivial. A lot of this came from looking at how @devblackops has devblackops/stucco setup.

Changes to the Actual Module

• I had to remove Plaster\ references in Plaster/InvokePlaster.ps1 because this was causing the builds to fail for Ubuntu and Mac.
• src was renamed to Plaster to allow BuildHelpers to more easily determine the module.
• test was renamed to tests.

Changes to Tests

• Tests now run in Pester 5
• Tests leverage BeforeDiscovery or BeforeAll where appropriate
  • This means that the shared script was no longer necessary.
• Tests now leverage the Test:\ directory.
  • In a few cases where file compares were necessary, we use a GetFullPath command (copied from Pester documentation) to

New Build

• Leverage PowerShellBuild and BuildHelpers helper modules to make building seamless.
  • Previous version was failing to build in PS7.
  • Variables wouldn't resolve neatly causing artifacts to end up in C:\.

Workflow Changes

• Extra workflows (including one in root) were removed.
• PesterReports workflow updated to use new build script + EnricoMi/publish-unit-test-result-action@v1
• Add new Publish workflow.
  • This will require adding the nuget api key to the github settings + grabbing a certificate from the appropriate location.

Minor Changes

• A few spacing changes due to auto format on save.
• Changes to the docs were auto generated.

[HeyItsGilbert]

Hopefully resolves #345. When folks submit PR's in the Future, they'll get a nice test result comment added. Something like https://github.com/HeyItsGilbert/Plaster/runs/3786247775?check_suite_focus=true

If you're curious what the actual build looks like: https://github.com/HeyItsGilbert/Plaster/runs/3786232749?check_suite_focus=true#step:4:1

[psjamesp]

Approved.