refactor: minor (#347)

* some refactoring

* accidental merge

* refactor: ensure all asserts have error message to avoid cryptic messages

* general refactoring

* move controller to create-plugin

src/core/structures/context.ts

@@ -114,7 +114,7 @@ export class Context extends CoreContext<Message, ChatInputCommandInteraction> {
         if ('interaction' in wrappable) {
             return new Context(Ok(wrappable));
         }
-        assert.ok(wrappable.isChatInputCommand());
+        assert.ok(wrappable.isChatInputCommand(), "Context created with bad interaction.");
         return new Context(Err(wrappable));
     }
 }