Video Block | Replace `RequireJS` with ES6 `import/export` #36527

[farhan]

In this ticket we are moving Video Block JS into xmodule/assets

It's an old tech-debt mentioned in this readme

This legacy code was discovered while working on #36282

As per the discussion in the @openedx/axim-aximprovements, @kdmccormick meeting , it has been decided that we will first convert the Video Block's JavaScript code from RequireJS to Vanilla JS within the edx-platform repository. Once this refactoring is complete, we will unblock the story extract the Video Block.
We will be extracting xmodule/assets/video JavaScript files into a xblocks-contrib repository.