feat: added spot ws service, moved client to common, refactoring

[vigodsky]

Hi,

Here I implemented Binance spot ws service and did some refactoring.

Common mechanics of websocket client I moved to common/websocket package (it's identical for each service, I don't want to have duplicates). Configuration of endpoint, using keep alive and other parameters can be used like in general way of this lib - from global vars of each package. So setting up common client can be done flexible and without breaking main architecture.

For example,
We can create futures.NewOrderPlaceWsService, which uses its own function to establish connection/resolving url/using keepalive and so on. Check code in constructor for more details.

I also tried to reduce some interfaces, change naming for better following SRP.

Thanks

[xyq-c-cpp]

good job, but somebody ask me some questions:

My question is regarding websocket reconnection. From the code I reviewed, it seems that keepalive is being handled for the ping/pong stream, but I don’t see any part of the code that disconnects the connection every 24 hours.

Has this functionality not been developed yet? If not, how can I resolve the issue of disconnection every 24 hours? (I would appreciate it if you could provide an example code.)`

can you answer that question?
@vigodsky