Hook up Telemetry LSP event and add telemetry event when users opt-out/in to features

[TylerLeonhardt]

needs PowerShell/vscode-powershell#3053 for the full flow.

The LSP has a message called telemetry event. The omnisharp lib gives us a mechanism for sending this so this PR hooks that up.
It's important to note that this doesn't make any requests besides sending a message to the client (aka vscode) to do the work of sending a telemetry event off the box. This way PSES doesn't have to depend on any AppInsights dll or something like that.

The event that this adds is an event called NonDefaultPsesFeatureConfiguration that has the body of settings that have been switched off/on from the default value. For example, if the user turns off the PackageManagement prompt (which defaults to on... aka true) then an event is fired with payload: { PromptToUpdatePackageManagement: false } where false is the new value it is being set to aka the non-default value.

This also modifies the E2E test to check to see if telemetry is sent when PSSA is turned off.

I also fixed a couple build warnings by adding Async to the end of all the test methods while I was touching it (sorry it makes the diff more annoying :( )

[TylerLeonhardt]

@david-driscoll I'd love your thoughts on this because I'm not quite happy with the experience of typing telemetry events. Right now the event takes an IDictionary<string, JToken> but ideally I can provide my own type and that gets serialized as my telemetry event... but I didn't see how to do that.

[david-driscoll]

you can make your own model with a custom element and things should "just work".

        [Parallel]
        [Method(WindowNames.TelemetryEvent, Direction.ServerToClient)]
        public class PsesTelemetryEventParams : IRequest
        {
            ...<properties>...
        }

and then send it using server.SendNotification(new TelemetryEventParams(), ct);

On the receiving side you would have do a little more work. options.OnNotification<PsesTelemetryEventParams>(WindowNames.TelemetryEvent, (@params) => {...});

[TylerLeonhardt]

@david-driscoll mentioned offline that there will be some work done to the telemetry event so that it accepts a custom type similar to launch/attach requests.

So I'll hold off on the refactoring until then.