In its current implementation, the VideoStatusLabel shows HD based on peer
connection stats. These stats will be available on temasys browsers soon but
will remain unavailable on Firefox, which does not collect height/width stats.
To support VideoStatusLabel showing cross-browser, move the high-definition
detection out of stat sniffing and instead check the video element itself using
an interval in LargeVideoManager. (An interval was used because the temasys
video object does not support the onresize event.) Also, add a cleanup path from
conference.web to LargeVideoManager to remove the interval.

Move the HD label into the newly renamed VideoStatusLabel
component. That way it cannot be possible for the audio only
label and the HD label to display simultaneously.

Audio only mode can be used to save bandwidth. In this mode local video is muted
and last N is set to 0, thus disabling all remote video.

When this mode is enabled avatars are shown.

Split language detectors to be web/native dependent. Take care of strings that contain html.

When callstats is not configured hide the button.

Recently, we reimplemented the watermarks in React. Unfortunately, we
didn't take into account film strip-only mode.

Additionally, we duplicated watermark-related source code on the Welcome
and Conference pages.