Adds support for cleaning up bootstrap containers in the

toos/cleanup-containers script.

Dynamic Ceph OSD bootstrap containers also included.

Change-Id: Ifb5b54c5b78a894ed6e8b9980a6eb9919e52364c
Closes-Bug: #1515544
Signed-off-by: Shaun Smekel <shaun.smekel@theorem.net.au>