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

Improve Panopto MATCH_URL regular expression

Some weird merged regressed #9407 when merging 2.2 in 2.3, and backporting the VP from 2.3 to 2.2 reintroduced the issue, so I reimplemented it

Add aria-label to whiteboard poll result

Prevent negative values being used in presentation height / width

Obsolete in html5 and also was breaking the message sanitizer

Only allow for https uri in welcome and modOnly messages

Allow img tag in welcome and modOnly messages

Add a minimum socket validation to full-audio connection

Sanitized modOnlyMessage prior to using it

Pulled HTML5 locales on July 29, 2020

Sanitize data v2.2 - Add tag br in whitelist

Sanitize data in addUser

Collect more bigbluebutton nginx access logs in bbb-conf --zip

Update lodash and node-sass versions

Prevent screen share cropping on chrome 84