feat: `startPresentation` URL parameter

[elzody]

• Resolves: #4051
• Target version: main

Summary

TODO

• [ ] Cypress tests?

Checklist

• [x] Code is properly formatted
• [x] Sign-off message is added to all commits
• [ ] Documentation (manuals or wiki) has been updated or is not required

[elzody]

i briefly spoke with méven from collabora in the matrix chat about this, and this was the response:

That's the current expected behavior, due to browser limitation, we can't open a real external presentation window so COOL is replaced by the presentation logic, this could be worked-around though. Browsers have added more restriction since the feature was implemented, this would need to be fixed for certain browsers

therefore, at least for now, given having to refresh the page, this should work cc: @juliusknorr

[juliusknorr]

All right, then let's stick with that as intended behavior

[juliusknorr]

Not sure if anything still left as it is in work in progress state still, but looks good from my side 👍