[Workloads] Move setup and aliasing out of Versions.props

[lewing]

Move

Note that reading from another property in Versions.props is an anti-pattern as this will have the wrong value when building from source. That overrides versions after the Versions.props import. We usually put things that read from Version.Details.props / Versions.props into Directory.Build.props.

Might not matter here if this path isn't exercised in source-build but wanted to mention it.

See https://github.com/dotnet/sdk/blob/0d31ba892465268a030b3563df0bddef39855f6e/Directory.Build.props#L97 for an example

Originally posted by @ViktorHofer in #121853