resolve SECURE_FETCH bugs

ERROR HANDLING FIXES

- use raise_for_status() to pass through response code
- handle exceptions where no response object is passed through

INSTANCE ACTOR

- models.User.objects.create_user function cannot take an ID
- allow instance admins to determine username and email for instance actor in settings.py

bookwyrm/settings.py

@@ -370,3 +370,8 @@ TWO_FACTOR_LOGIN_MAX_SECONDS = 60
 HTTP_X_FORWARDED_PROTO = env.bool("SECURE_PROXY_SSL_HEADER", False)
 if HTTP_X_FORWARDED_PROTO:
     SECURE_PROXY_SSL_HEADER = ("HTTP_X_FORWARDED_PROTO", "https")
+
+# AUTHORIZED_FETCH Instance Actor
+# WARNING this must both be unique - not used by any other user
+INSTANCE_ACTOR_USERNAME = DOMAIN
+INSTANCE_ACTOR_EMAIL = f"representative@{DOMAIN}"