Move handlers to a common-handlers role

Move the handlers into a common-handlers role that can be included via a
role dependency.

Change-Id: I00f0ae24beb1a84ebf5fafde4556e6f0983d6521
Networker node changes

The networker node needs to have the bridge set up prior
to applying the hostgroup

Change-Id: I38990511832ad55b41bdc36c7eded037add74731
PAUSED: Use `git resume` to continue working.