Send Application Service Events (#477)

* Prevent sql scanning into nil value in accounts_table

Signed-off-by: Andrew Morgan <andrewm@matrix.org>

* Remove uneccessary logging, null checking

* Don't forget to set the localpart

* Simplify error checking

* Store And Send Application Service Events

* Modify INSTALL.md and dendrite-config.yaml for the new appservice database
* Correct all instances of casing on 'application service' to align with
spec
* Store incoming events that an app service is interested in in the
database to be later read by transaction workers.
* Retrieve these events from transaction workers, one per AS.
* Minimal transaction ID data is stored as well to recover after
server failure.
* Send events to AS and exponentially backoff on failure.

Signed-off-by: Andrew Morgan <andrewm@matrix.org>

* Finish my own sentences.

* Fix up database interaction

* Change to event-based AS sending

* Reduce cyclomatic complexity

* Appease the errcheck gods

* Delete by int ID instead of string.

This was causing some events to not be deleted, as < an eventID doesn't
really make much sense.

* Check if there are more events to send before sleeping

* Send same transaction if last send attempt failed

* Don't backoff on non-200s, tight send loop, 1 event query

* Remove tight send loop. Fix events not being deleted

* Additionally order by event id, track main.go

* Return the last txnID, which our events are using

* Remove old main.go file

* Prevent duplicate events from being sent...

* Strip event content if it doesn't contain anything

Signed-off-by: Andrew Morgan <andrewm@matrix.org>

* Update gomatrixserverlib and use Unsigned AS event prop

* Fixes

* Fix sync server comment
* Remove unnecessary printlns
* Use logrus Fields
* Worker state methods
* Remove sillyness

* Fix up event filtering

* Handle transaction event limit in loop

* Switch to using a sequence for transaction IDs

* Don't verify self-signed AS certificates

* Fix logging

* Use gmsl.Event instead of AS-only event in transactions

Also clear up the logic on lookupStateEvents a little bit.

* Change invalid_txn_id to global (for efficiency)

* Use a bool for EventsReady instead of an int

vendor/manifest

@@ -135,7 +135,7 @@
 		{
 			"importpath": "github.com/matrix-org/gomatrixserverlib",
 			"repository": "https://github.com/matrix-org/gomatrixserverlib",
-			"revision": "38a4f0f648bf357adc4bdb601cdc0535cee14e21",
+			"revision": "929828872b51e6733166553d6b1a20155b6ab829",
 			"branch": "master"
 		},
 		{