Git - refactor ref pickers (#201411)

* Refactored quick picks

* Another set of refactoring

* Moved over the remaining classes

* git.checkoutType setting should only be used by the Checkout quick pick

* Introduce RefProcessor and cleanup code

* Introduced multiple processor types

* Another round of refactoring

extensions/git/package.nls.json

@@ -64,12 +64,12 @@
 	"command.deleteBranch": "Delete Branch...",
 	"command.renameBranch": "Rename Branch...",
 	"command.cherryPick": "Cherry Pick...",
-	"command.merge": "Merge Branch...",
+	"command.merge": "Merge...",
 	"command.mergeAbort": "Abort Merge",
 	"command.rebase": "Rebase Branch...",
 	"command.createTag": "Create Tag",
-	"command.deleteTag": "Delete Tag",
-	"command.deleteRemoteTag": "Delete Remote Tag",
+	"command.deleteTag": "Delete Tag...",
+	"command.deleteRemoteTag": "Delete Remote Tag...",
 	"command.fetch": "Fetch",
 	"command.fetchPrune": "Fetch (Prune)",
 	"command.fetchAll": "Fetch From All Remotes",