comp AP gateway: signature checking, caching and threads management: - HTTP signature is checked for incoming messages - AP actor can now be followed using pubsub subscription. When following is accepted, the node is cached - replies to posts are put in cached pubsub comment nodes, with a `comments_max_depth` option to limit the number of comment nodes for a root message (documentation will come to explain this). ticket 364

--- a/sat/core/exceptions.py	Tue Mar 22 17:00:42 2022 +0100
+++ b/sat/core/exceptions.py	Tue Mar 22 17:00:42 2022 +0100
@@ -123,6 +123,11 @@
     pass
 
 
+class EncryptionError(Exception):
+    """Invalid encryption"""
+    pass
+
+
 # Something which need to be done is not available yet
 class NotReady(Exception):
     pass