feat: export everything from entry points

[aarthificial]

This PR introduces new ES bundles for both core and 2d. They contain the same things as the lib directory, except rolled up into one single file.

As of right now, they are not published to npm to prevent mistakenly mixing them with the contents of the lib directory.
In v4, the lib directories will be removed and replaced with these bundles.

To make it possible, all entities should now be imported directly from the package's entry point:

import {all, createRef} from '@motion-canvas/core';
import {makeScene2D, Circle} from '@motion-canvas/2d';

Importing from subdirectories will continue working until v4.