create a ceph_rest package

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
pybind: remove flask from python-ceph requirements

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
pybind: move rest.py to ceph_rest/__init.py

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
pybind: correct the ceph_rest path for the deprecation warning

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>