change global flag to a list of serverIds and if it is empty it will be global

lib/src/main/java/net/tomatentum/marinara/interaction/commands/annotation/ApplicationCommand.java

@@ -12,5 +12,5 @@ public @interface ApplicationCommand {
     public String description() default "";
     public String[] aliases() default {};
     public CommandOption[] options() default {};
-    public boolean isGlobal() default false;
+    public long[] serverIds() default {};
 }