Lower the margin between video thumbnails

Fix for the size of remote desktop sharing videos

prosody plugin to make all users owners/moderators

This reverts commit b09e8635.

No Temasys alert on mobile (Web)

Be consistent about formatting within 1 and the same file.

If half the file is written in ES6, it is easier to read if the rest of
the file is in ES6 as well. If ES6 is used, then const is better than
let. If source code is shorter yet as readable as the long version, then
prefer the short version.

We have the functions reload and redirect which modify window.location.
Use them and do not directly modify window.location so that we have
fewer places of direct window.location modifications and it is easier to
refactor them.

window.location calls it reload so util/helpers shouldn't call it
redirect because UI/util/UIUtil has it is own redirect which is the
assign of window.location.

- use proper punctuation
- fix markdown syntax
- always use syntax highlighting
- document missing commands
- miscellaneous grammar fixes

- Use 1 name for 1 abstraction. Instead of useFullScreen and enabled use
  fullScreen.
- Comments are correct English sentences so no double spaces between
  senteces, no capitalization of the work On midsentence.
- Write as little source code as possible if readability is preserved.
- Utilize Facebook's Flow.
- The name of a private function must start with _ and the jsdoc should
  state that the function is private.

The implementation varies across platforms, with the same goal: allow the app to
use the entire screen real state while in a conference.

On Android we use immersive mode, which  will hide the status and navigation bars.

https://developer.android.com/training/system-ui/immersive.html

On iOS the status bar is hidden, with a slide effect.

fix: Respect the disableRtx config option.

Included a patch to prosody-trunk which allows owners to kick each other

When callstats is not configured hide the button.