Core Tools OOP Host

[aishwaryabh]

Issue describing the changes in this PR

resolves #3744

This PR creates the feature branch feature/oop-host, which has the OOP host build. This PR also includes checks for the user passing in the --runtime param specifying the host and infers the host if that is not specified. I've also added tests which checks that we try to execute the correct func.exe (even though those tests technically fail since there is no inproc-6 or inproc-8 folder). We also only run on .NET 8 TFM and remove multi-targeting in the feature branch.

For when the user specifies the --runtime parameter, these are the following scenarios we support today where the first row is the options the user may put in and the first column are the potential apps a user may have:

	inproc6	inproc8	default
.NET Isolated app			x
.NET 6 in-proc app	x
.NET 8 in-proc app		x
non .NET app			x

Anything that does not have an X within it throws an error to the user with a helpful message on why the passed in host runtime is not valid.

For inference the path will be:

	Sequence	Tool version
.NET Isolated app	default	default
.NET 6 in-proc app	default -> inproc6	inproc6
.NET 8 in-proc app	default -> inproc8	inproc8
non .NET app	default	default

This is how the logic looks like today for the inference scenario:

• If app is in-proc app
  • If FUNCTIONS_INPROC_NET8_ENABLED is set
    - Run inproc8 host
  • Else
    - Run inproc6 host
• else
  • Run OOP host

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

[fabiocav]

Initial review iteration.

[kshyju]

Where do we use the --no-build argument?

[aishwaryabh]

We use it in line 626?

[fabiocav]

The table shared above doesn't seem to capture the expected supported scenarios.

Shouldn't this reflect what is supported when --runtime is explicitly set?

	inproc6	inproc8	default
.NET Isolated app			x
.NET 6 in-proc app	x
.NET 8 in-proc app		x
non .NET app			x

For inference, the path would always be:

	Sequence	Tool version
.NET Isolated app	default	default
.NET 6 in-proc app	default -> inproc6	inproc6
.NET 6 in-proc app	default -> inproc8	inproc8
non .NET app	default	default

EDIT: This information was applied to the PR description

[fabiocav]

Can we move this logic that is specific to .NET to a different method and out of RunAsync? That will help declutter this method and make the code easier to navigate.

[fabiocav]

This will also enable you to reduce the variables as you'll be able to drive the logic without needing to have an additional flag for OOP.

[aishwaryabh]

Moved this logic into: ShouldExitAfterDeterminingHostRuntime to clean up RunAsync