Added Initial cephadm smoke test

[sunilkumarn417]

• Added downstream cephadm.
• Code changes to update downstream registry and cephadm installation with RPM enabled.
• Added initial smoke test.

[sunilkumarn417]

Successful execution log path - magna002:/home/sunnagar/teuth/03-07-20-1593773165-cephadm/teuthology.log

[sunilkumarn417]

http://magna002.ceph.redhat.com/sunnagar-2020-07-07_01:34:44-smoke:cephadm-master-distro-basic-clara/380773/teuthology.log