Add a check if user exists before running method

- Adds a default style to buttons
- Remove <meta> tag from message

- Few improvements to video tabBar
- Add translations to action links

Time and again , the direct mention of "Jitsi" , either in watermark or settings or release notes, causes our user base to freak out and enter long drawn discussions of how video over the web should be accomplished.    

With no disrespect to our FOSS partner, we need to start calling this a Rocket.Chat Group VideoChat feature - powered by Jitsi to ease the fear factor.

* Start on Jitsi Package

* add package files

* initial proof of concept ui skeleton

* Basic working jitsi implementation

* Added ssl flag to jitsi meet constructor

* Try UI that auto starts call on tab open

* Add timeout for name setting

* fix the room width when flextab is 790px wide

* Adds admin settings for Jitsi;
Calls jitsi:connect on tabbar open and disconnect on close;
Uses instance_id + room_id for jitsi id;

* changed JitsiMeet ssl flag.  Flag now means no SSL.  So its going to use ssl by default

* Add SSL option for Jitsi;
Fixed ESLint errors found

* Default Jitsi SSL to true

* Adds option of colors into tabbar;

* Made settings public

* Make settings public; Add blinking support;

* Started on call timeout

* clearInterval and dispose

* Clean up and keep from showing multiple instances.

* switch setInterval and setTimeout to Meteor methods

* move api.dispose into defer.  Switch back to non-verbose logging on external_api.js

* removed debug logging

* Remove un-needed header on template

* Move external_api.js inside for onprem that don't allow any external

* Allow actionLinks server side as well as client side

* Add the ability to add an icon with the actionLink

* Added messageType and actionLink to join call.  Fixed timeout issues

* Allow Jitsi for Channels

* remove watermark - confuses some naiive users

* Added Beta warning.  Fixed some bugs changing rooms

* Fixed some eslint issues