doc: gerrit: update gerrit links and screen shots with LF infra

Updated all the links and references for gerrit to the new gerrit
in LF. Also updated the screenshots to show the new gerrit and
project name.

Change-Id: If56b230379fad4de58032f9d729e6a94f27389ed
Signed-off-by: Javier B Perez <javier.b.perez.hernandez@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
11 files changed