Orchestration for creating app management groups.

This adds:
- A Celery beat task for enqueuing application creation tasks
- A Celery task for creating the application
- Payload and Response dataclasses for creating management groups

It also does some incidental cleanup.

tests/domain/cloud/test_payloads.py

@@ -0,0 +1,72 @@
+import pytest
+
+from pydantic import ValidationError
+
+from atst.domain.csp.cloud import (
+    AZURE_MGMNT_PATH,
+    ManagementGroupCSPPayload,
+    ManagementGroupCSPResponse,
+)
+
+
+def test_ManagementGroupCSPPayload_management_group_name():
+    # supplies management_group_name when absent
+    payload = ManagementGroupCSPPayload(
+        creds={}, display_name="Council of Naboo", parent_id="Galactic_Senate"
+    )
+    assert payload.management_group_name
+    # validates management_group_name
+    with pytest.raises(ValidationError):
+        payload = ManagementGroupCSPPayload(
+            creds={},
+            management_group_name="council of Naboo 1%^&",
+            display_name="Council of Naboo",
+            parent_id="Galactic_Senate",
+        )
+    # shortens management_group_name to fit
+    name = "council_of_naboo"
+    for _ in range(90):
+        name = f"{name}1"
+
+    assert len(name) > 90
+    payload = ManagementGroupCSPPayload(
+        creds={},
+        management_group_name=name,
+        display_name="Council of Naboo",
+        parent_id="Galactic_Senate",
+    )
+    assert len(payload.management_group_name) == 90
+
+
+def test_ManagementGroupCSPPayload_display_name():
+    # shortens display_name to fit
+    name = "Council of Naboo"
+    for _ in range(90):
+        name = f"{name}1"
+    assert len(name) > 90
+    payload = ManagementGroupCSPPayload(
+        creds={}, display_name=name, parent_id="Galactic_Senate"
+    )
+    assert len(payload.display_name) == 90
+
+
+def test_ManagementGroupCSPPayload_parent_id():
+    full_path = f"{AZURE_MGMNT_PATH}Galactic_Senate"
+    # adds full path
+    payload = ManagementGroupCSPPayload(
+        creds={}, display_name="Council of Naboo", parent_id="Galactic_Senate"
+    )
+    assert payload.parent_id == full_path
+    # keeps full path
+    payload = ManagementGroupCSPPayload(
+        creds={}, display_name="Council of Naboo", parent_id=full_path
+    )
+    assert payload.parent_id == full_path
+
+
+def test_ManagementGroupCSPResponse_id():
+    full_id = "/path/to/naboo-123"
+    response = ManagementGroupCSPResponse(
+        **{"id": "/path/to/naboo-123", "other": "stuff"}
+    )
+    assert response.id == full_id