Added support of per-extension assembly isolation

[veler]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• New feature or enhancement
• UI change (please include screenshot!)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Internationalization and localization
• Other (please describe):

What is the current behavior?

Issue Number: fix #1430

What is the new behavior?

Added a AssemblyLoadContext per extension discovered in DevToys, which allows each extension to load every assemblies it needs in an isolated manner. This allows .NET to load and use multiple versions of an assembly at the same time.

Note: This feature is NOT supported by Android, iOS and WebAssembly. But we don't care since we don't target them.

Validation

You can test the change by building and installing the 2 extensions in this ZIP:
ExtensionTest.zip

Other information

Quality check

Before creating this PR:

• Did you follow the code style guideline as described in CONTRIBUTING.md
• Did you build the app and test your changes?
• Did you check for accessibility? On Windows, you can use Accessibility Insights for this.
• Did you verify that the change work in Release build configuration
• Did you verify that all unit tests pass
• If necessary and if possible, did you verify your changes on:
  • Windows
  • macOS
  • Linux

[jerone]

Confirmed that this fix works:

And also in my extension:

Windows 10

[veler]

Confirmed that this fix works:

And also in my extension:

Windows 10

Awesome! Thank you for taking the time to verify :D