CloudMigrations: Implement snapshot management apis (#89296)

* add new apis

* add payloads

* create snapshot status type

* add some impl

* finish implementing update

* start implementing build snapshot func

* add more fake build logic

* add cancel endpoint. do some cleanup

* implement GetSnapshot

* implement upload snapshot

* merge onprem status with gms result

* get it working

* update comment

* rename list endpoint

* add query limit and offset

* add helper method to snapshot

* little bit of cleanup

* work on swagger annotations

* manual merge

* generate swagger specs

* clean up curl commands

* fix bugs found during final testing

* fix linter issue

* fix unit test

pkg/services/featuremgmt/registry.go

@@ -709,7 +709,7 @@ var (
 			AllowSelfServe:    false,
 			RequiresRestart:   true,
 		},
-		FeatureFlag{
+		{
 			Name:              "disableClassicHTTPHistogram",
 			Description:       "Disables classic HTTP Histogram (use with enableNativeHTTPHistogram)",
 			Stage:             FeatureStageExperimental,