Enable build of Linux Arm64 RPM packages

[NikolaMilosavljevic]

We need to start building arm64 RPM packages. There is a lot of interest in enabling this.

Runtime repo produces a subset of the packages.

For complete end-to-end experience, here's the list of other repos that need to enable arm64 RPMs:

• dotnet/aspnetcore: Enable build of Linux Arm64 RPM packages aspnetcore#40252
• dotnet/installer: Enable build of Linux Arm64 RPM packages installer#13230

Backport to 6.0 servicing after 7.0 is merged.

[NikolaMilosavljevic]

[Triage] @NikolaMilosavljevic please ensure there are issues for aspnetcore and installer repos.