Adding aligned structure and segmenting the configguide.

Adding aligned structure and segmenting the configguide.

Also set heading levels for readability and added missing licence headers.
Copied the header where I copied content, so please be mindful and inform me if you disagree.
Removal parts of userguide duplicated with configguide. Take the others into faq.rst
Removal duplicated references in installerconfig.
Removal redundant png files.
Release notes update for Brahmaputra release.

Change-Id: I6e1a101107752f4bc7b6e3bbaea0738690d07af8
Signed-off-by: ChristopherPrice <christopher.price@ericsson.com>
Signed-off-by: Justin-chi <chigang@huawei.com>
(cherry picked from commit 3eab3cd722870e6c02ee1337d3536dc68f89b13e)