Reduce number of columns

If we reduce the number of video columns to 2 (default = 5) a maximum of 10 videos are shown.

https://community.jitsi.org/t/pagination-unstable-release-question/102238/30

Changed for fairmeeting.net

 TILE_VIEW_MAX_COLUMNS: 2,

in /etc/jitsi/meet/brand/fairmeeting.net/interface_config.js

This should reduce load on browsers #34 (closed) and cause less bandwidth problems.