Add OpenStack docs jobs to ironic.

Also add the requirements job.

Change-Id: I52c30b8024a1087778d2295c20c1d9706b9ea92c
Reviewed-on: https://review.openstack.org/30907
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Elizabeth Krumbach Joseph <lyz@princessleia.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins
Adds Chef style checking job

Adds a macro that fires off tailor to check cookbooks
Chef and Ruby style.

See https://review.openstack.org/#/c/30827 for some
more information about the use of tailor against the
Chef cookbook repositories.

Marks the OpenStack Compute cookbook for gating with
this new job.

Change-Id: Ib5b3d6548749ddc1107a70b462f7432dde672410
Reviewed-on: https://review.openstack.org/30921
Reviewed-by: John Dewey <john@dewey.ws>
Reviewed-by: craigtracey <craigtracey@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins