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

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.
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> Might not matter here if this path isn't exercised in source-build but wanted to mention it.
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> See https://github.com/dotnet/sdk/blob/0d31ba892465268a030b3563df0bddef39855f6e/Directory.Build.props#L97 for an example

_Originally posted by @ViktorHofer in [#121853](https://github.com/dotnet/runtime/pull/121853/files#r2588414931)_