feat!: Drop the sample web-client temporarily (#368)

as it's currently not working for at least two different reasons:

Commit(43afb6a): 'Implement JSON serialization on most built-in data types.',

which broke the JS parsing and updating of subscribed values.
And the other being

Commit(eab4caa): 'Rewrite the client to be async all the way through',

which indirectly halted subscriptions for servers implemented with this crate (#324).

Re-adding this sample would be highly appreciated.
If possible with tests, which might prevent its recurring decay.

Cargo.toml

@@ -16,7 +16,6 @@ members = [
  "samples/simple-server",
  "samples/chess-server",
  "samples/discovery-client",
- "samples/web-client",
  "samples/event-client",
  "tools/certificate-creator"
 ]

README.md

@@ -68,5 +68,4 @@ The full list of samples:
 4. [`chess-server`](samples/chess-server) - an OPC UA server that connects to a chess engine as its back end and updates variables representing the state of the game.
 5. [`demo-server`](samples/demo-server) - an OPC UA server that is more complex than the simple server and can be used for compliance testing.
 6. [`mqtt-client`](samples/mqtt-client) - an OPC UA client that subscribes to some values and publishes them to an MQTT broker.
-7. [`web-client`](samples/web-client) - an OPC UA client that subscribes to some values and streams them over a websocket.
-8. [`event-client`](samples/event-client) - an OPC UA client that will connect to a server and subscribe to alarms / events.
+7. [`event-client`](samples/event-client) - an OPC UA client that will connect to a server and subscribe to alarms / events.

docs/async_client.md

@@ -47,7 +47,7 @@ The old client, by accident or on purpose, did not support pipelining requests,
 
 The service traits are gone. They were entirely unused, except as a way to group services, and potentially as a way for users to have mocking? Keeping them would have been possible, but it would have required a higher MSRV.
 
-Callbacks have changed slightly, mostly due to the way notifications are received. The subscription logic is similar, but the way `MonitoredItems` queued values seemed largely meaningless, as they were always immediately dequeued (or if they weren't that would be a user error?), it seemed like a feature that was mostly unhelpful. The connect/disconnect callbacks are also gone, though they could be reimplemented. It is possible to monitor the state of the session by watching the output of the event loop `poll` method, see the `web-client` sample for an example of how this could be done.
+Callbacks have changed slightly, mostly due to the way notifications are received. The subscription logic is similar, but the way `MonitoredItems` queued values seemed largely meaningless, as they were always immediately dequeued (or if they weren't that would be a user error?), it seemed like a feature that was mostly unhelpful. The connect/disconnect callbacks are also gone, though they could be reimplemented. It is possible to monitor the state of the session by watching the output of the event loop `poll` method.
 
 The client is no longer behind a lock. Any locking is internal, except for access to the subscription cache directly. This should be a strictly positive change for usability.