Allow remote images and videos to excercises

[shlomiassaf]

Use case

Adding locally hosted images is a burden to the server and as a task when one wants to add additional metadata to an excercise.

One will need to save the image localy, then upload it.

With video that's more complicated.
There are tons of YouTube guides out there which can be used.

On top of that, there the licencing issues, which require vetting it for every upload, especially on public gyms and wger.de
With embedded videos, it's solved, we let YouTube handle it.

Now, there an issue here with broken links, which might become an issues later on.
For that a follow up feature can be monitoring for borken linkes, and alerting/removing them.

I Say YouTube due to its wide-spread content and simple integration, but any source is fine