Updating BuildAndTest.proj to explicitly uninstall extensions from a previous build before installing new ones.

Capture exception info for integration test failures

Will capture the exception stack trace in addition to the screen shot
when a first chance exception occurs running our integration tests.

Support adding PackageReferences to CPS projects

Add support for inspecting Solution Explorer items

We need this version to avoid conflicts with other assemblies that
reference a different version of the System.Composition.* assemblies.

We're on a background thread already, so we can just block on the calls to `AddAsync` and `RemoveAsync`.

Add APIs to allow integration tests to add PackageReferences to CPS projects.

Add basic support for inspecting Solution Explorer items.

changed logger to log errors from all analyzers not just first analyzer

made diagnostic engine to verify span given to diagnostic from analyz…

Optimize fast path for "Use 'var'" code style

Update IDE Test Plan with 15.3 features

Properly push events to the OOP side so that we know when things like solution-closing happens.
Fixes #19768

Include Commit in our NuGet package

made diagnostic engine to verify span given to diagnostic from analyzers. and added explicit check in tagger for out of range

Move over to the new ITextImage platform API.

Some performance and reliability fixes around file change tracking

Switch back to the UI thread when cleaning up the solution in integration tests.