rpc: Allow configuring the underlying tungstenite WebSocket connection

[romac]

Osmos nodes regularly send messages over WebSocket which are 250MB in size, which is more than the default max_message_size setting of the underlying WebSocket connection. Because of this, such messages are currently rejected by the underlying library and trigger an error within Hermes, which then also completely misses the message.

While we will eventually move away from the current event-based model in Hermes, and will therefore not need to use the WebSocket client anymore, we are not there yet and would like to see if we can figure out a way to receive such messages (what this will do to the performance of the relayer remains to be seen).

The easiest way to experiment with this would be to expose the underlying tungstenite::protocol::WebSocketConfig in tendermint_rpc, either directly or by using a facade that can convert into that.

What's the definition of "done" for this issue?

The WebSocketClient takes an optional tungstenite::protocol::WebSocketConfig parameter which will be use to configure the underlying WebSocket connection.