Notification of string changes

Author: Sara Arjona
MDL-72407 videojs: Remove videojs-flash and videojs-swf libraries
Apart from removing these libraries because the Flash Player was deprecated
in 2017 and officially discontinued on 31 December 2020, the rtmp and useflash
settings have been removed too (they make no sense anymore).


http://git.moodle.org/gw?p=moodle.git;a=commit;h=2a3527ccb0788006ab71ae59e35f7051b6fe2716
http://github.com/moodle/moodle/commit/2a3527ccb0788006ab71ae59e35f7051b6fe2716

+ 4.0 en [configaudioextensions,media_videojs]
+ 4.0 en [configvideoextensions,media_videojs]
+ 4.0 en [pluginname_help,media_videojs]