Add file manifest for runtime and targeting pack

[jkotalik]

Fixes #10215 and #10216

This seems to be working locally for win-x64. I want to confirm things look good on CI before I do some finalization.

Few open questions that I'm working on solving:

• For the runtime pack manifest, make sure manifests are in the right location and have the right names (may need clarification here as it wasn't clear in the issues)
• Determine which dlls should be in which manifest (should native dlls be in the targeting pack?)

I'd also like to add a few automated tests once I confirm things are correct.

[jkotalik]

@dsplaisted I think I need to run this PR by you to make sure I'm producing the right manifests in the correct locations.

[jkotalik]

Verified the targeting pack and the runtime pack work locally. For the runtime pack, I change the KnownFrameworkReference to a local dev build of the M.A.App.Runtime.win-x64 and made sure restore/build worked. dotnet run failed from System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Bcl.AsyncInterfaces, Version=1.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified., however, I think this is due to me not targeting an equivalent version of Microsoft.NetCore.App.Runtime.win-x64.

I'll be on top of verifying this once it gets merged into core-sdk and can react quickly.

[JunTaoLuo]

nit: FrameworkList => RuntimeList. these are different files so the property names should probably follow suite.

[jkotalik]

How much do you care about this? PR is green and I'd rather not wait another 2 hours for a rebuild on a rename like this if you have no other feedback.