Convert CoreManager and controllers to ES modules

[dplewis]

New Feature / Enhancement Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am not just asking a question.
• [x] I have searched through existing issues.

Current Limitation

Controllers are currently plain JS objects and their types are created and maintained separately in the CoreManager. These types are easily overlooked and aren't up to date.

Feature / Enhancement Description

Move the controllers to a separate folder /Controllers. Converting to ES Modules will allow for type generation without having to manually update types in the CoreManager. We can then re-export the types if we need to.

Example Use Case

Controllers/SessionController.ts

  export function getSession(options?: RequestOptions): Promise<ParseSession> {
    const RESTController = CoreManager.getRESTController();
    const session = new ParseSession();

    return RESTController.request('GET', 'sessions/me', {}, options).then(sessionData => {
      session._finishFetch(sessionData);
      session._setExisted(true);
      return session;
    });
}

CoreManager.ts

import * as SessionController from './Controllers/SessionController.ts';

// Can now be deleted
type SessionController = {
  getSession: (options?: RequestOptions) => Promise<ParseSession>;
};

type Config = {
...
SessionController?: SessionController;
...
};

setSessionController(controller: SessionController) {
  requireMethods('SessionController', ['getSession'], controller);
  config['SessionController'] = controller;
},

getSessionController(): SessionController {
   return config['SessionController']!;
},