Bryan Beck

#2373 Add option to use trackAvailability() instead of trackEvents() in applicationInsightsPublisher

4

**What this PR does / why we need it**: Provide an option to publish healthCheck metrics through the `TelemetryClient.TrackAvailability()` method. With this approach, healthCheck metrics are stored within the "AvailabilityResults"...

The current implementation of the ApplicationInsightsPublisher publishes healthCheck results through the `TelemetryClient.TrackEvent()` method. As a result, healthCheck metrics are stored within the "customEvents" table of application insights. The built-in web-test...