[feature] Add admin media prune orphaned CLI command (#1146)

* add FilePath regex

* add `admin media prune orphaned` command

* add prune orphaned function to media manager

* don't mark flag as required

* document admin media prune orphaned cmd

* oh envparsing.sh you coy minx

internal/config/flags.go

@@ -178,3 +178,10 @@ func AddAdminTrans(cmd *cobra.Command) {
 		panic(err)
 	}
 }
+
+// AddAdminMediaPrune attaches flags pertaining to media storage prune commands.
+func AddAdminMediaPrune(cmd *cobra.Command) {
+	name := AdminMediaPruneDryRunFlag()
+	usage := fieldtag("AdminMediaPruneDryRun", "usage")
+	cmd.Flags().Bool(name, true, usage)
+}