Tracing via dotnet ActivitySource

[T-Gro]

• Reducing the Activity surface to a minimum
• Removing redundancy with existing Logger module , in this casing tracing (= ActivitySource) is more appropriate and semantically correct
• Bringing up consistent naming
• Covering the surface area of BackgroundCompiler (full for any non-trivial public action) and FsharpChecker (if not being just a wrapper over background compiler)
• Selecting a few heavier below the call stack for further nested activity tracking
• Wrapping the existing ReportTime (used by fsc for example) so that it produces activities as well

[T-Gro]

@safesparrow

I have done steps o bring this up to date and make a few extensions and cleanups. I hope this 2-step-PR process will work, especially not sure if my merging actions will get reflected also in the original PR to main repo.

[safesparrow]

Thanks. The PR is showing lots of files changed. I suspect it's because it contains recent changes from master. Ill have a look at resolving this.

[T-Gro]

Yes, I merged with origin/master to get it to a fresh state .