Add video uploading

[lediable]

Hi!

It would be nice to be able to upload a video referred to a powerlift with the possibility of adding a comment like "today squat wasn't deep enough"

[yusifsalam]

@lediable

I'm planning a feature where you'll be able to add a youtube link to any set , so you'll have to first upload to youtube manually and then feed the youtube link to the set.