Arg lists for fetch and checkout module calls

Previously custom module calls were hardcoded with the repo as an
argument. This change allows a list to be defined for module calls
and will automatically map the keyword __REPO__ to the repo name.
This change also adds a fetch module call to match the checkout
call.

Change-Id: I27fcaadcd085385034208a8fb2dbfafce06e1656
Merge "Arg lists for fetch and checkout module calls" into production