Improve checking of webhooks and ffmpeg

fix HT slide title

Update bbb-conf

One more step for upgrade ffmpeg

RaP: Don't error on pencil drawings with 0 dataPoints

 - display meeting is about to end warning to user and breakout warni…

In some cases, we get DRAW_END events for pencil shapes from the
html5 client that have no dataPoints. The only thing we can really
do here is detect the issue and ignore the shape.

In some cases, this may result in the shape's intermediate drawing
updates being shown, but it'll disappear when the end event happens.

Add check for ffmpeg

Fix #5736

 - no locales to update

 - include .tx/config so we can pull locales

RaP: Convert aspect ratio numbers to int before checking value

The checks for 0 numerator or denominator were failing due to
type mismatch

Two chat improvements

Add support for HTML5 client in Edge

Update bbb-webrtc-sfu packages to use MKV profile for recordings via kurento api

RaP: Store rendered audio temp file in target directory, not archive_dir

Add a loading bar for WebRTC screenshare start up in the Flash client

The archive_dir can by the raw recording directory in some recording
formats - including, hopefully, presentation at some point (to avoid the
extra copy)

  Implement end meeting callback url

   To use, add meta_endcallbackurl parameter on the create api call.

HTML5: Enable push chat notifications by default

Merge branch 'v2.0.x-release' of https://github.com/bigbluebutton/bigbluebutton into orientation-recording