Also sync libraries

Change-Id: I60d6b713c152c14b5af37b5c87308c72408801e3

* charm-helpers sync for classic charms
* charms.ceph sync for ceph charms
* rebuild for reactive charms
* sync tox.ini files as needed
* sync requirements.txt files to sync to standard

Change-Id: I512ef8bbb52c08e782c66450b435a40a76b8a532

Drop use of local copy of ceph_broker.py in preference to the
centrally maintained copy in charms.ceph.

Change-Id: I89aa0f9fc7d5d2d480ebabc1cb17a86dcbef21bf

All OpenStack Charms now contain identical tox.ini files,
not to be modified or made unique within each charm repo.

This is to ensure consistency across charm repos in tox
target naming, approach and purpose, also giving the
charm dev and test experience additional consistency.

Also create empty dirs with .keep files where necessary.
Some classic charms have actions and/or lib dirs, and some
do not. In all classic charms, flake will now check those
dirs to ensure lint coverage of existing or future content.

Manually fix up test names, Makefile and other legacy
artifacts remaining from basic ceph-proxy on an old copy
of ceph-mon.

Change-Id: I54eb35d0e449f203237bdc9f065551a1fbc887a0