Update dev-setup.rst

Adding docker part (inspired by https://tuleap.net/plugins/forumml/message.php?group_id=101&list=1&topic=30207). Still missing the "don't reboot" part. I'll add it once I understand why.
Adding LDAP config for docker
Fixing layout

'cuz rSt is one big ticklish basterd
Fix wording

Virtual box was too close from Oracle VB
Merge branch 'master' of https://github.com/Aryess/tuleap-documentation-en into Aryess-master

 * Add docker section in developper guide
Merge branch 'Aryess-master'

 * Add docker section in developper guide