Moving diagnostics into a service (#14832)

* Moving diagnostics into a service

* Fixing golint checks

* Fixing tests

* Renaming from diagnostics to telemetry

* Adding missing files

* Initializing telemetry earlier in the server startup

* Fixing tests

* Adding a log for the telemetryID initialization error

* Addressing PR review comments

* Fixing merge problem

* Removing some extra Diagnostics mentions

* Making tests pass

plugin/api.go

@@ -109,6 +109,12 @@ type API interface {
 	// Minimum server version: 5.10
 	GetDiagnosticId() string
 
+	// GetTelemetryId returns a unique identifier used by the server for telemetry reports.
+	//
+	// @tag Server
+	// Minimum server version: 5.28
+	GetTelemetryId() string
+
 	// CreateUser creates a user.
 	//
 	// @tag User