feature(backups): add backup structures and queries

selfprivacy_api/graphql/common_types/backup_snapshot.py

@@ -0,0 +1,9 @@
+import datetime
+import strawberry
+
+
+@strawberry.type
+class SnapshotInfo:
+    id: str
+    service_name: str
+    created_at: datetime.datetime

selfprivacy_api/graphql/common_types/service.py

@@ -1,7 +1,9 @@
 from enum import Enum
 import typing
 import strawberry
+import datetime
 from selfprivacy_api.graphql.common_types.dns import DnsRecord
+from selfprivacy_api.graphql.common_types.backup_snapshot import SnapshotInfo
 
 from selfprivacy_api.services import get_service_by_id, get_services_by_location
 from selfprivacy_api.services import Service as ServiceInterface
@@ -101,6 +103,10 @@ class Service:
         """Get storage usage for a service"""
         return get_storage_usage(self)
 
+    @strawberry.field
+    def backup_snapshots(self) -> typing.Optional[typing.List[SnapshotInfo]]:
+        return None
+
 
 def service_to_graphql_service(service: ServiceInterface) -> Service:
     """Convert service to graphql service"""

selfprivacy_api/graphql/queries/backup.py

@@ -0,0 +1,14 @@
+"""Backup"""
+# pylint: disable=too-few-public-methods
+import typing
+import strawberry
+from selfprivacy_api.graphql.common_types.backup_snapshot import SnapshotInfo
+
+
+@strawberry.type
+class Backup:
+    backend: str
+
+    @strawberry.field
+    def get_backups(self) -> typing.List[SnapshotInfo]:
+        return []