Produce Dotnet.Installation library package for internal testing in dnup ci

[nagilson]

• Modifies the CI pipeline that was created to properly produce a nukpg of the dotnet installation library.
• The original CI pipeline was incomplete but put in-place so that dnceng could make a pipeline off the yml file. This corrects some of those issues.
• The signing in the pipeline tests, internal, appears to be failing. I believe that's because we're blocked from signing outside of a protected release branch. We'll need this to flow in via automated CI to fix that issue.
• Does not publish the package outside of pipeline artifacts. We'll add that in the next step, in which we'll also be able to verify if CI needed to run for the signature to work, or if there are other issues.
• I tried to build using the arcade step but encountered some issues like missing workloads - example:

  Errors: MSB4276: The default SDK resolver failed to resolve SDK "Microsoft.NET.SDK.WorkloadManifestTargetsLocator" because directory "D:\a\_work\1\s\.dotnet\sdk\10.0.100-rc.1.25420.111\Sdks\Microsoft.NET.SDK.WorkloadManifestTargetsLocator\Sdk

Since it seems to be trying to produce a signature without arcade, I'll pursue the simpler path first.

[nagilson]

merging so #51463 can run checks as we decided to pivot to a new branch