add stub structure with comments to cephdeploy

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add subrepo sections with the ability to extend

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add a load function that parses the config file

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>