Obtain more email settings from environment

We also provide the defaults as they are in Django, instead of
implicitly setting them to None.

.env.example

@@ -10,12 +10,13 @@ LOGGING_HANDLERS_LEVEL=INFO
 LOGGING_LOGGERS_LEVEL=INFO
 LOGGING_LOGGERS_DJANGO_LEVEL=INFO
 TESTING_DIR=/app/general/tests/files/
-FEATURE_FLAG=''
 EMAIL_HOST=''
-EMAIL_USE_TLS=True
 EMAIL_PORT=587
+EMAIL_USE_TLS=True
 EMAIL_HOST_USER=''
 EMAIL_HOST_PASSWORD=''
+DEFAULT_FROM_EMAIL=''
+SERVER_EMAIL=''
+EMAIL_SUBJECT_PREFIX=''
 EMAIL_BACKEND_CONSOLE='True/False'
-EMAIL_USE_TLS=True
 SECRET_KEY=''

.env.testing

@@ -10,4 +10,3 @@ LOGGING_HANDLERS_LEVEL=INFO
 LOGGING_LOGGERS_LEVEL=INFO
 LOGGING_LOGGERS_DJANGO_LEVEL=INFO
 TESTING_DIR=/home/runner/work/term_platform/term_platform/app/general/tests/files/
-FEATURE_FLAG=''

app/app/settings.py

@@ -167,11 +167,15 @@ def __contains__(self, address):
 
 
 # Email settings
-EMAIL_HOST = os.environ.get("EMAIL_HOST")
-EMAIL_HOST_USER = os.environ.get("EMAIL_HOST_USER")
-EMAIL_HOST_PASSWORD = os.environ.get("EMAIL_HOST_PASSWORD")
-EMAIL_PORT = os.environ.get("EMAIL_PORT")
-EMAIL_USE_TLS = os.environ.get("EMAIL_USE_TLS")
+EMAIL_HOST = os.environ.get("EMAIL_HOST", "localhost")
+EMAIL_PORT = os.environ.get("EMAIL_PORT", 25)
+EMAIL_USE_TLS = os.environ.get("EMAIL_USE_TLS", False)
+EMAIL_HOST_USER = os.environ.get("EMAIL_HOST_USER", "")
+EMAIL_HOST_PASSWORD = os.environ.get("EMAIL_HOST_PASSWORD", "")
+DEFAULT_FROM_EMAIL = os.environ.get("DEFAULT_FROM_EMAIL", "webmaster@localhost")
+SERVER_EMAIL = os.environ.get("SERVER_EMAIL", "root@localhost")
+EMAIL_SUBJECT_PREFIX = os.environ.get("EMAIL_SUBJECT_PREFIX", "[Django] ")
+ADMINS = os.environ.get("ADMINS", "").split()
 
 email_backend_env = os.environ.get("EMAIL_BACKEND_CONSOLE", "False").lower() in ["true", "1", "yes"]