Support BLE Mesh

**Describe the problem you have/What new integration you would like**
Native support of BLE mesh technology.

**Please describe your use case for this integration and alternatives you've tried:**
Meshing of all BLE devices so that range and signal is reliable. I am not aware of an alternative in the ESPHOME ecosystem.

**Additional context**
There was an interesting discussion on the HA Facebook group around the increasing quality and variety of BLE devices available. What interested me was the potential to replace more expensive ZWAVE technology.

But the natural limitation of BLE is range.

Native support for BLE Mesh would be a fantastic addition to ESPHome as it would natively network all sensors together, and allow specific placement of an ESP32 to act as a repeater/amplifier to pass blackspots.