api: get_snapshot_details
api: get_snapshot_details

That's basically conversion work between what the storage_service returns
and the json types.

Signed-off-by: Glauber Costa <f8b79557d19b40666ebe336545a0b6178af65685@scylladb.com>

scylladb/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,raphaelsc/scylla,avikivity/scylla,kjniemi/scylla,raphaelsc/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,raphaelsc/scylla,kjniemi/scylla,kjniemi/scylla