Ability to test selected repos on daily or PR build of MSBuild

At the moment MSBuild lacks the tests on real life projects. This creates constraints on new feature development, also increases risks of regression while fixing the issues while developing new features or fixing the issues.
When discovered internally, those issues lead to involvement of MSBuild team members to investigate those.
Frequently, those issues are not related to MSBuild.

The user story suggests implementing the infrastructure allowing to test selected repos with daily or PR built MSBuild.
Ideally both scenarios should be supported:
- the repo is built on arcade
- the repo is not built on arcade - selected open-source project

The MSBuild used on CI build for these repos should be replaced with daily build of MSBuild.

Ideally:
- it should be relatively easy and well documented on how to onboard a new repo if there is a need to do it
- performance improvements/regression should be assessed as well

# Justification:
- decrease the risk of regression
- decrease the time spent on 1st / 3rd party support troubleshooting the issues