extend user manual for setting up bluetooth communication.

This extends the user manual for setting up bluetooth communication.

Signed-off-by: Jan Schubert <Jan.Schubert@GMX.li>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Documentation: update formatting

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Documentation: add pictures for Bluetooth setup

Signed-off-by: Jan Schubert <Jan.Schubert@GMX.li>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>