Deprecate CloudstackSnitch and remove duplicate code in snitches

The patch also refactors existing cloud snitches to get rid of the duplicate code,
this is the logical follow-up of CASSANDRA-16555 where AbstractCloudMetadataServiceConnector was introduced.

patch by Stefan Miklosovic; reviewed by Jacek Lewandowski, Jackson Fleming and Maxwell Guo for CASSANDRA-18438
19 files changed