fixed typo

Empty After= may confuses systemd

This patch fixes a typo in bbb-record causing problems by checking the
bigbluebtuuon user.

This patch modifies `bbb-record` allowing the user `bigbluebutton` to
delete recordings. The user has all necessary access rights, meaning
that the deletion works without a problem and the check for root does
not protect anything. The users owns the data after all. The current
check just makes things less convenient.

Using this larger value helps reducing ocurrences 1005/1010 errors for Chrome, avoiding an openssl's error which interrupts the dtls handshake (Chrome triggers "DTLS timeout expired" error)
This key size is also the default value used by freeswitch on switch_core_cert.c

Added shortcuts for enableHTML5CameraQualityThresholds and enableHTML5WebcamPagination

Only wav files in freeswitch cache directory were deleted. With this PR also opus files are deleted.