system default python is now usually python3 - better make our code
compliant with it
`ceph` CLI itself has some slightly different usage and outputs
jq used instead of cut in a few places, because was easier to work out
what the original commands were intending to grab, now that those
outputs have moved location. Yes, jq is a new dependency for some of
the plugins, but it was already implicitly depended upon in ceph_osd
plugin
Break up some functions into more manageble steps.
If json from ceph is invalid, handle it correctly (i.e. dont return anything)
Handle larger chunks of data from ceph (100k instead of 10k per osd).
