Build installers at the end of the repo build and allow building with desktop msbuild

[ViktorHofer]

Build the Installer projects after everythign else got built by adding a new Traversal project that
builds all P2Ps in it in parallel.

Fixes #58984 Unblocks dotnet/sdk#44828

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Summary of the changes (Less than 80 chars)

Description

{Detail}

Fixes #{bug number} (in this specific format)

[ViktorHofer]

Adding the NO MERGE label until I fully tested the changes inside the VMR

[wtgodbe]

Local Development job failures are unrelated

[ViktorHofer]

@ellahathaway this will fix the Sign and Publish issue as well inside the VMR.