Replace twitter, video and image processors

Commented, please see remarks above.

Generally, change see to go into the right direction, but I dislike including the improvement of our ER-formatter here.
This should gets its own dedicated issue, so it appears properly in release notes. When doing so, it gets its own description why it is needed, and should come with some quick kernel test to demonstrate how it works correctly from a simple isolated API perspective. Maybe best, let's still have this issue, do it first, and then get back to finishing up here?

per last remark.

I pretty much got ( / extracted) the OK to merge this when it's done, though.

I'll merge this as soon as i have the work on 📌 Convert gallery processor Needs work done (so that MR won't be 'polluted' with this one).

Any remarks on the EntityReferenceCeFieldFormatter / VideoEmbedCeFieldFormatter I'll still happily address in a followup.

Automatically closed - issue fixed for 2 weeks with no activity.