If the screen is rotated by default Android destroys the
activity and recreates it. This causes issues if a child and
parent are already paired, as the connection is lost.
To prevent Android from destroying the Activity, instead
invoke a configuration change on an orientation or resize.
This commit adds the shell of the MonitorActivity. This activity
will register its service on the local network, wait for a connection,
then send audio data.
The StartActivity is the first activity which will be launched
in the baby monitor, and in the future will list the two main
options: become a monitor or a listener.
