Fixes: #7296

- Disables the invite buttons while invites are ongoing
- Adds a keyboard shortcut (Enter) to send out invites
- Closes AddPeopleDialog upon successful invites sent
- Fixes the SecurityDialog closing when trying to set E2EE key via Enter shortcut
- Removes superfluous separator from SecurityDialog

The lobby feature adds the possibility to lock a meeting and only allow people in after virtually knocking and going through formal approval

* The prejoin page always displays the 'join without audio' option.
* The join button will be disabled if there is no input.
* Fix some CSS for the case when the user is not anonymous.

* Add a checkbox for skipping the prejoin page on next use. (This is hidden for
now, until we also have a settings entry for it).
* Rework 'Join by Phone' buttons and add new overlay.
* Update the device status accordingly if there were errors while adding
devices.
* The input is filled with the display name if there was one previously used.
* Join the meeting on 'Enter' press.

Reason: On Safari the foreign object is not scaled correctly.

Some CSS fixes are also included.

This reverts commit faf24ca7ec.

This reverts commit 08f55ccb94.

It's been considered too disruptive and will often misfire especially
if there are issues with the data channels.

* ref(web): removes video blur when ICE is disconnected.

Removes the blur effect from the large video and stops showing
the network connectivity issues message when ICE disconnects.

The feature has been considered too disruptive and there's a plan to
have it replaced with a more subtle indication.

* remove RECONNECTING key from main.json

* ref(Filmstrip): Optimize resizes.

* fix(thumbnails): resize.

* fix(thumbnails): Issue with height 0, width 0.

* doc(Filmstrip): Improve JSDoc.