Simplify the Azure CI configuration + Several fixes
Simplify the Azure CI configuration + Several fixes

- Don't try to have one config for rakudo, nqp and MoarVM. This simplifies
  the config a lot.
- Fix building of PRs
- Shorten job names for better readability

nbrown/rakudo,tony-o/rakudo,salortiz/rakudo,MasterDuke17/rakudo,rakudo/rakudo,tony-o/rakudo,labster/rakudo,MasterDuke17/rakudo,rakudo/rakudo,nbrown/rakudo,salortiz/rakudo,labster/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,rakudo/rakudo,tony-o/rakudo,tbrowder/rakudo,tbrowder/rakudo,tbrowder/rakudo,salortiz/rakudo,labster/rakudo,MasterDuke17/rakudo,rakudo/rakudo,MasterDuke17/rakudo,nbrown/rakudo,salortiz/rakudo,tbrowder/rakudo,tony-o/rakudo,rakudo/rakudo,tony-o/rakudo,labster/rakudo,labster/rakudo,labster/rakudo,MasterDuke17/rakudo,tony-o/rakudo,tbrowder/rakudo,nbrown/rakudo,nbrown/rakudo,rakudo/rakudo,salortiz/rakudo,salortiz/rakudo,nbrown/rakudo