Adjusted headings

Adjusted the headings in the installation & config guide, scenario description
and user guide. Also removed the relese notes from the install and config doc
since you have a separate document for this.

Change-Id: I2ecbaebe2c0f337cca0a8d0ad130fa97eceabe78
Signed-off-by: Sofia Wallin <sofia.wallin@ericsson.com>
(cherry picked from commit a5f72bd195d6a6cf510e415e589fddcd83f9481e)