auth: add several AnonymousUser method stubs

We'll need to use these, so this commit implements them here
with tests for coverage.

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/auth.py

@@ -53,10 +53,30 @@ class AnonymousUser:
     def is_authenticated():
         return False
 
+    @staticmethod
+    def is_trusted_user():
+        return False
+
+    @staticmethod
+    def is_developer():
+        return False
+
+    @staticmethod
+    def is_elevated():
+        return False
+
     @staticmethod
     def has_credential(credential):
         return False
 
+    @staticmethod
+    def voted_for(package):
+        return False
+
+    @staticmethod
+    def notified(package):
+        return False
+
 
 class BasicAuthBackend(AuthenticationBackend):
     async def authenticate(self, conn: HTTPConnection):