Show Current Activity

For admin users, adds an icon in the header with the current number of sessions which links to a current activity dashboard to show session information.

To use the icon, an upgrade to fontawesome to the latest version was needed so heavy QA should be done to ensure I didn't miss any pesky little icons from appearing huge.

Also might want to wait to merge this until some kinks with the streaming client & session query are worked out (see bottom right episode for examples - audio says it's a video container, transcode resolution is wrong, etc. I will make a new issue for these).

To Do:

• informational tooltip w/ info regarding what throttled / transmux mean
• add play progress bar