RenameTableEvent, plus write connection track_event() mechanism (#2682)

* Add track_event callback to execute_write_fn and write_wrapper

Allows write functions and write_wrapper generators to queue events
during a write operation that are dispatched after successful commit.
The fn or wrapper can optionally accept a `track_event` parameter
(detected via call_with_supported_arguments). Events are discarded
if the write raises an exception.

Does not yet handle the block=False (non-blocking) case - events
queued during non-blocking writes are currently silently discarded.

Refs https://github.com/simonw/datasette/issues/2681

* Dispatch track_event events for non-blocking (block=False) writes

Spawns a background asyncio task that awaits the write thread's reply
queue and dispatches pending events after a successful non-blocking
write. Events are still discarded if the write raises an exception.

Refs https://github.com/simonw/datasette/issues/2681

* Warn that events won't fire for other processes

Refs https://github.com/simonw/datasette/issues/2681#issuecomment-4157118662

docs/plugins.rst

@@ -261,7 +261,8 @@ If you run ``datasette plugins --all`` it will include default plugins that ship
             "templates": false,
             "version": null,
             "hooks": [
-                "register_events"
+                "register_events",
+                "write_wrapper"
             ]
         },
         {