[MM-41576] Revamp database schema version (#19586)

* revamp db version and add applied migrations endpoint

* replace old schema version with new

* add db version subcommand

* add to local api

* reflect review comments

* log errors

* remove setting the version from model.CurrentVersion

* fix a test

api4/config_test.go

@@ -577,7 +577,7 @@ func TestGetOldClientConfig(t *testing.T) {
 		config, _, err := client.GetOldClientConfig("")
 		require.NoError(t, err)
 
-		require.NotEmpty(t, config["Version"], "config not returned correctly")
+		require.Empty(t, config["Version"], "config not returned correctly")
 		require.Empty(t, config["GoogleDeveloperKey"], "config should be missing developer key")
 	})