move manifest project from repos.xml into actual attributes and work on update.py

The updater script now supports reading a repos.xml file and updating all
github manifests automatically

Signed-off-by: Constantin Runge <uroc327@cssbook.de>
remove hardware stuff... (every device must depend on its hardware repos)

Signed-off-by: Constantin Runge <uroc327@cssbook.de>
Let update.py handle remotes without manifest file and add the manifest xmls

Signed-off-by: Constantin Runge <uroc327@cssbook.de>