Add refresh SSTables stage

[karol-kokoszka]

After the corresponding SSTables are copied to the destination node, there is a need to call Scylla server to refresh given keyspace and column_family.

scylla-manager/v3/swagger/scylla_v1.json

Line 11841 in b501137

"/storage_service/sstables/{keyspace}": {

This must be done per node.
In the context of node, per keyspace and per column_family.