re-implement CLoudBackupSnapshots

[mgmonteleone]

• [x] test_00_test_get_for_cluster
• [x] test_01_test_get_for_snapshot
• [x] test_02_create_snapshot
• [x] test_03_restore_snapshot_to_atlas
• [x] test_04_restore_snapshot_to_atlas_bad_snapshot_id
• [x] test_06_restore_snapshot_to_atlas_bad_same_cluster
• [x] test_07_get_restore_job_for_cluster
• [x] test_08_get_one_restore_job
• [x] test_09_is_valid_snapshot_false
• [x] test_10_is_valid_snapshot_true
• [x] add test for handling when no snapshots exist. (test_00_test_get_for_cluster)

[mgmonteleone]

Tests passed on CI.