refs #7587 - add jquery_pwstrength_bootstrap asset gem

Paired with https://github.com/theforeman/foreman/pull/1840 as I'm assuming this isn't a runtime dep.

http://koji.katello.org/koji/taskinfo?taskID=168229 f19
http://koji.katello.org/koji/taskinfo?taskID=168230 el6
http://koji.katello.org/koji/taskinfo?taskID=168231 el7