LP1834208 Removing apache2-websockets

LP1834208 Removing apache2-websockets

Remove code and build components for apache2-websockets.  Update
documentation to reflect the use of websocketd as the only supported
OpenSRF websockets implementation.

Add a note to the install documentation indicating websocketd does not
offer a configurable inactivity timeout, but this can be accomplished
by running it behind a proxy.

Update NGINX and HAPROXY example configs to reflect the assumption that
websocketd is runs locally without SSL by default.

Signed-off-by: Bill Erickson <berickxx@gmail.com>