Merge branch '2.3-alpha5-with-split-meteor-roles-10349' of github.com:antobinary/bigbluebutton into 2.3-alpha5-with-split-meteor-roles-10349

multiple automated tests suites updates + add missing polling specs and move them with old ones to a polling test suite (#10766)

* updating old tests + collecting more snapshots [WIP]

* updates old test suites and collects more visual regressions screenshots

* remove snapshots and their collection temporary

* run tests from packages.json

* update test execution command/export constants from .env to core/constants.js

* update tests/puppeteer/README.md file

* update LOOP_INTERVAL variable call and assign timeouts to the webcam share spec

* redefine waitForSelector func in page.js, update chat test suite specs and add poll chat message test spec

* Merge remote-tracking branch 'upstream/develop' into updating-old-tests-visual-with-visual-regressions

* update webcam test specs collecting videoPreviewTimeout and use it to wait for videoPreview selector

* update custom parameters test suite

* update breakout test suite

* update webcam layout test suite

* update multiusers test suite

* update notifications test suite

* update presentation test suite

* whiteboard test suite

* screenshare test suite

* update sharednotes test suite

* user ELEMENT_WAIT_TIME variable from timeouts constants.js

* list TEST CONSTANTS by category

* add poll test suite and assigns the right unassigned timeouts

* set test pages to headless

Merge branch 'develop' of github.com:bigbluebutton/bigbluebutton into 2.3-alpha5-with-split-meteor-roles-10349

Fix user-list-item dropdowns breaking on mobile screen sizes

Store the changed and default settings in different variables

Show uploaded slides from other users

Added STUN check

Chat with adapter and context 

fix inserts userId to the EndMeeting function calls.

Fixes interruption of webcam, external video and screenshare when user changes language settings

User role is incorrect after client reconnect.

fix for issue: https://github.com/bigbluebutton/bigbluebutton/issues/11182

preserve bbbWebAPI and sharedSecret over upgrades

Set safe default values for slide position (WIP)

Fix lost output audio when change client language

Skip echo test in breakout room

Make screen reader announce status changes in userlist

Fix rendering after public chat cleared

Customize systemd unit files

Currently there is a mechanism in bbb-config which adds overlay units.
This is not neccesary because sbt allows you to specify your own unit
files.