feat: allow sending email directly via mailgun API as an option

requirements.txt

@@ -9,6 +9,8 @@ psycopg2==2.8.4
 celery==4.2.1
 django-picklefield==1.1.0
 
+django-anymail==8.4
+
 python-dateutil>=2.8
 unicodecsv==0.14.1
 bleach==3.3.0

settings.py

@@ -150,12 +150,20 @@ INSTALLED_APPS = (
     'django.contrib.contenttypes',
     'django.contrib.sessions',
     'django.contrib.sites',
+    'anymail',
     ## HELIOS stuff
     'helios_auth',
     'helios',
     'server_ui',
 )
 
+ANYMAIL = {
+    "MAILGUN_API_KEY": get_from_env('MAILGUN_API_KEY', None),
+}
+
+if ANYMAIL["MAILGUN_API_KEY"]:
+    EMAIL_BACKEND = "anymail.backends.mailgun.EmailBackend"
+
 ##
 ## HELIOS
 ##