Add RateLimitLogger to unify rate-limit warnings

[zegarekk]

Summary

This PR adds a new helper class RateLimitLogger to xchange-core to standardize how API rate-limit warnings are logged.

Motivation

Different exchange modules currently log rate-limit issues inconsistently.
The new class ensures that all such warnings:

• follow the same format
• are throttled to avoid log flooding
• improve observability for developers and CI systems

Changes

• Added new file: xchange-core/src/main/java/org/knowm/xchange/utils/RateLimitLogger.java
• Updated xchange-binance and xchange-kraken modules to use it (example in next commit)

Benefits

✅ Unified rate-limit log format
✅ Reduced log spam
✅ Easier future maintenance

Checklist

• Code compiles successfully
• Unit-tested locally
• No external dependency added
• Backward compatible
• Additional integrations planned (stream modules)

Example output