Fixes: #689, #690
Refactor container inspection code into a package of its own with some
rudimentary tests. Use this package consistently in osd commands dealing
with containers.
Improvements for the next PRs:
* implement API to fetch info about container by ID (to avoid fetching
full list)
* handle and display errors on client side, not to the log of the
server
* more tests, including k8s containers (how can we do that?)
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
