Adjusted the docs structure according to directives

Adjusted the docs structure according to directives

created subdirectory:
docs/installationprocedure/images
and copy both screenshots to this subdirectory.

Updated according to comment

Added a sub directory /installationprocedure and  move the feature
configuration to here
Moved the abstract from the userguide/index.rst to the feature.userguide.rst
Added a new index.rst in accordance to the new /installationprocedure

Change-Id: Ie2acaddc1746fcee5baaca79713ea253c7d3f1b0
Signed-off-by: Sofia Wallin <sofia.wallin@ericsson.com>
(cherry picked from commit d6e752f195525b396dad47ab339102120cd550e1)