* Use embedded resources for ProximityExpressionsGetter tests

* Move breakpoint resolver down into Features

This reverts a workaround added in
https://github.com/dotnet/roslyn/pull/39159
which allowed us to keep our build and integration tests on 16.3.

* Refactoring

* Refactoring

* Refactoring

* Feedback

* Misc feedback

* Use ValueTask instead of custom task caching

Editor team recently added a new GetSuggestedActions API overload that allows providing a more detailed operation scope message. This PR moves us to that API for Roslyn suggested actions. We now display the name of the executing analyzer/fixer/refactoring when user hits Ctrl + Dot to bring up the light bulb. This should help the users identify the slow extension and help us in improving performance of our analyzers/fixers/refactorings.

* Remove unused ExternalAccess projects

* Add external access shims for TypeScript editor features layer.

* Feedback

* Use wrapper pattern

* Add nullable checks, clean up

* Use -Implementation and -Wrapper suffixes

Replaces the existing "Full Solution Analysis" option, with a background analysis scope to allow users to control the analysis scope for all solution crawler based background analysis.

Fixes #38429. Active file scope minimizes all the background analysis to the active files, saving on CPU consumption from background analysis on remaining files in the solution.

I have also updated up the low virtual memory listener which detects low VM and used to turn off just the full solution analysis to now set the background analysis scope to "Active file" for the current session.

* Remove project type from Bing URI

* Add Language to DiagnosticData

* Trim arguments that are too long

Given this is not a reliable crash, my guess is the problem is we are
sometimes processing an older Solution snapshot. Asking a specific
SourceText for the specific ITextSnapshot it came from could fail
if that snapshot had been GC'ed, whereas going to the container
first and asking for the buffer directly should be more reliable. Either
way we now also handle the null case.

Fixes https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1010045

At this point, the nullable support in the semantic model seems stable,
and there's no reason for somebody to manually turn this on since any
project that is using nullable will turn it on automatically.

This removes the hard dependency on the editor packages so we can
still support loading in 16.3. The unit tests must be disabled that
depend on the new support, but everything else will continue to
function.

This removes all direct use of IIndentationManagerService and allows
us to light up if the MEF part is available. Reflection is used to
call methods on the interface.

IIndentationManagerService is a new service from the editor that looks
at the existing tabs and spaces in a file and attempts to determine
what the prevailing format is. This is useful for repositories that
may have not had an .editorconfig to specify what is happening, or for
repositories that have such a mix that an .editorconfig may not be
useful.

Enable logging of informational telemetry for analyzers/fixers/refactorings executed during Ctrl + .

If user enables informational RoslynEventSource telemetry following the steps at https://aka.ms/reportPerf, we log the execution times for each analyzer/fixer/refactorings when computing the code fixes and refactorings to show in the light bulb. This will help us identify slow analyzers/fixers/refactorings that lead to UI delays with "Gathering suggestions" dialog.