This one resolves #1605 and #1583 - it adds loaders based on placeholders for the following views:

• video playback
• channel
• search

It's based on #1618 so probably makes sense to review that one first, although it shouldn't bee too hard to review either way.

There are 2 issues:

• There's a problem with video preview heights in the carousel, but it should be solved once Add Mobile And Table Screens #1562 is merged:

• In the video view, once the video metadata finishes loading and the placeholder is hidden, the player goes to 0 height for a brief moment. I've tried a couple of things and I'm not sure how to solve it so left it for now. I will come back to this and possibly consult @Gamaranto on what we could do