Add support for apparmor security profiles

Install apparmor profile for ceph-osd processes, and provide
associated configuration option to place any ceph-osd processes
into enforce, complain, or disable apparmor profile mode.

As this is the first release of this feature, default to disabled
and allow charm users to test and provide feedback for this
release.

Change-Id: I4524c587ac70de13aa3a0cb912033e6eb44b0403