Localize notification_utils to the Admin!

This changeset copies everything in notifications_utils to turn into a local project module.  It includes dependency changes to account for this adjustment and the notifications_utils tests.  It also fixes all of the import statements.

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

notifications_utils/clients/redis/__init__.py

@@ -0,0 +1,13 @@
+from datetime import datetime
+
+from .request_cache import RequestCache  # noqa: F401 (unused import)
+
+
+def total_limit_cache_key(service_id):
+    return "{}-{}-{}".format(
+        str(service_id), datetime.utcnow().strftime("%Y-%m-%d"), "total-count"
+    )
+
+
+def rate_limit_cache_key(service_id, api_key_type):
+    return "{}-{}".format(str(service_id), api_key_type)