MAC whitelisting for bt proxy

**Describe the problem you have/What new integration you would like**

I may wrong but my current understanding is that the esp32 bt proxy transparently forwards on all bt traffic it detects. In crowded locations with a lot of bt devices from within the home and also from neighbours in high density apartments, it would be good to have a configurable whitelist of MAC addresses which are forwarded. All others not in the whitelist are just ignored.

**Please describe your use case for this integration and alternatives you've tried:**

Reduce unnecessary forwarding.

**Additional context**