Enforce unique AuthServicesInfo (#618)

Alter user field to OneToOneField
Migration to enforce uniqueness pre-change
Migration to ensure all users have an AuthServicesInfo
Receiver to automatically create one upon user creation
Replace AuthServicesInfo.get_or_create with get
Prevent deletion of AuthServicesInfo from admin site
Remove add and delete permissions from model.

Get character names in chunks on corpstats update to prevent HTTP400 when requesting >350(ish) names

Include corpstats docs.
Update settings docs.

hrapplications/views.py

@@ -19,7 +19,7 @@ logger = logging.getLogger(__name__)
 
 
 def create_application_test(user):
-    auth, c = AuthServicesInfo.objects.get_or_create(user=user)
+    auth = AuthServicesInfo.objects.get(user=user)
     if auth.main_char_id:
         return True
     else:
@@ -31,7 +31,7 @@ def hr_application_management_view(request):
     logger.debug("hr_application_management_view called by user %s" % request.user)
     corp_applications = []
     finished_corp_applications = []
-    auth_info, c = AuthServicesInfo.objects.get_or_create(user=request.user)
+    auth_info = AuthServicesInfo.objects.get(user=request.user)
     main_char = None
     if auth_info.main_char_id:
         try: