Localize notification_utils to the API

This changeset pulls in all of the notification_utils code directly into the API and removes it as an external dependency.  We are doing this to cut down on operational maintenance of the project and will begin removing parts of it no longer needed for the API.

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

app/schema_validation/__init__.py

@@ -4,6 +4,7 @@ from uuid import UUID
 
 from iso8601 import ParseError, iso8601
 from jsonschema import Draft7Validator, FormatChecker, ValidationError
+
 from notifications_utils.recipients import (
     InvalidEmailError,
     InvalidPhoneError,