* [tests] Add a unit test project to test our net5 support.
* [tests] Fix clearing environment variables when launching processes.
* [tests] Add net5 macOS test app.
* [tests] Add net5 tvOS test app.
* [tests] Add net5 watchOS test app.
* [msbuild] Exclude CreateAppBundleDependsOn from net5 builds as well.
* [msbuild] We're not required to know the signing identity to figure out the app extension bundle name.
Rolf Bjarne Kvinge