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/plugintest/api.go

@@ -1916,6 +1916,20 @@ func (_m *API) GetTeamsUnreadForUser(userId string) ([]*model.TeamUnread, *model
 	return r0, r1
 }
 
+// GetTelemetryId provides a mock function with given fields:
+func (_m *API) GetTelemetryId() string {
+	ret := _m.Called()
+
+	var r0 string
+	if rf, ok := ret.Get(0).(func() string); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(string)
+	}
+
+	return r0
+}
+
 // GetUnsanitizedConfig provides a mock function with given fields:
 func (_m *API) GetUnsanitizedConfig() *model.Config {
 	ret := _m.Called()