Switch to YAML Syntax for Logging

This patch switches to using a much more readable YAML syntax for the
logging configuration in the HTML5 client.

On my server 2.3 alpha, the method metadata_for(meeting_id) gives back {}
(empty Hash). Thus "return if meeting_metadata.nil?" does not occur.

Does @redis.hgetall give {} instead of nil, even though there is a comment in
node_modules/redis/lib/utils.js "hgetall converts its replies to an Object. If
the reply is empty, null is returned"???

Virtualized user list

Allow polling when presentation does not exist but chat is available

Merged 2.2.22 into 'develop'

video-provider: normalize hidden cameraProfiles constraints

Also add some inlined docs to settings.yml

Improve poll results in public chat

Notify users when presentation is available for download

Allow more tags in welcome message/ mod only message

Pulled HTML5 locales Aug 10, 2020

Improve log for parsed passed parameter error

Remove muteAll and muteAllExceptPresenter from breakouts

Updated meteor-node-stubs and postcss-nested

Update filenames for saved public chat / users list

video-provider: remove unused app.video.stats locales

video-provider: dynamic video profiles (aka automatic bitrate/frame rate throttling)

video-provider: UI improvements

Backport PRs #8374 and its follow-ups #8888 and #8758 into 2.2

Restore activity check modal.

Improve Panopto MATCH_URL regular expression

kudos @pedrobmarin