Produce project-specific PackageVersions.props file

[oleksandr-didyk]

Part of #2482

Given the ability to retrieve project's dependency versions (#3040), a PackageVersions.props file should be produced based on current and previous source-built versions.

It can differ from the current implementation and be one specific file instead of a combination of two (static previous SB versions and dynamic current SB versions)

[oleksandr-didyk]

Expected implementation time -> 3-5 working days

[MichaelSimons]

Given the ability to retrieve project's dependency versions (#3040), a PackageVersions.props file should be produced based on current and previous source-built versions.

To clarify, the PackageVersions.props should only contain the versions for the dependencies discovered in #3040.

[premun]

Coincidentally, I have a class that can help here too:
https://github.com/dotnet/arcade-services/blob/main/src/Microsoft.DotNet.Darc/src/DarcLib/Models/VirtualMonoRepo/AllVersionsPropsFile.cs
or maybe
https://github.com/dotnet/arcade-services/blob/4cf29ede51d0cc12e43e94dee79bb9449ba55cb4/src/Microsoft.DotNet.Darc/src/DarcLib/Models/MsBuildPropsFile.cs#L32

These are dictionaries that serialize to/from a simple .props file.