Move devstack hooks from infra config to solum repo

To minimize the work done in infra project and reduce the dependency, let us
have code in solum repository and invoke the same from devstack job.

Solum part is here [1].

[1] https://review.openstack.org/65507

Change-Id: I0f763b20f60d56ffd7e1630303c1e936f80f61d8
Merge "Move devstack hooks from infra config to solum repo"