Add quota of concurrent meetings per template, add informations while
selecting a template, check server availability, show the template of
the meeting in admin./edit table, permanent meeting can be disabled,
dates of non-permanent meeting are strictly observed and mandatory,
duration of meeting is exact (+ 1 minute)...

Use an opt-out flow for comments in video, springify notifications and
notifications handlers

OO-4080: Possibility to use a rubric (evaluation form) to calculate the score of the manual scoring course node

Implement a strategy to concurrently migrate the metadata to database
both from the upgrader and the users, fix issues how the error messages
are sent by WebDAV (404...)