Abstract event validation/fetching, add outlier and signing key DB trees

Fixed the miss named commented out keys in conduit-example.toml.

conduit-example.toml

@@ -23,11 +23,11 @@ port = 6167
 max_request_size = 20_000_000 # in bytes
 
 # Disable registration. No new users will be able to register on this server
-#allow_registration = true
+#allow_registration = false
 
 # Disable encryption, so no new encrypted rooms can be created
 # Note: existing rooms will continue to work
-#allow_encryption = true
+#allow_encryption = false
 #allow_federation = false
 
 #cache_capacity = 1073741824 # in bytes, 1024 * 1024 * 1024