Add WebSocket rate limiting

[chredeur]

Motivation

I often use fastapi-limiter and noticed that a similar feature was missing in quart-rate-limiter.
This PR introduces WebSocket rate limiting, inspired by fastapi-limiter, while keeping the setup simple.

Summary

Adds WebSocket rate limiting that automatically reuses the same store as your HTTP rate limiter no extra configuration required!

What’s New

• WebSocketRateLimiter class with a fastapi-limiter-compatible API
• WebSocketRateLimitException for handling rate limit violations
• Automatic store sharing between HTTP and WebSocket rate limiting
• Works with all existing backends (Memory, Redis, Valkey)

How It Works

# Set up your rate limiter as usual
redis_store = RedisStore("redis://localhost:6379/0")
RateLimiter(app, store=redis_store)

# The WebSocketRateLimiter automatically uses the same Redis store
@app.websocket("/ws")
async def websocket_endpoint():
    ratelimit = WebSocketRateLimiter(times=1, seconds=5)

    while True:
        try:
            data = await websocket.receive()
            await ratelimit(websocket, context_key=data)
            await websocket.send("Hello!")
        except WebSocketRateLimitException:
            await websocket.send("Slow down!")

No need to configure your stores twice it works out of the box and keeps HTTP and WebSocket limits in sync.