Add Espressif System Zigbee

[lhespress]

Add Espressif System Zigbee

[lhespress]

@puddly PTAL

[Hedda]

    znsp = (
        "ZNSP = Espressif Zigbee NCP Serial Protocol: ESP32-H2, ESP32-H4, ESP32-C6",
        zigpy_espzb.zigbee.application.ControllerApplication,
    )

Nitpicking and probably trivial but still slightly confusing if it should be referred to as "ZNSP" or "ESPZB"? Also brought it up here:

• [SUGGESTION] Rename new radio type from znsp to either espznsp or espzb instead (so less easy to confuse/misstake for znp) lhespress/zigpy-espzb#11

and

• Add Espressif System Zigbee radio library support zigpy-cli#45 (comment)

PS: I am dyslectic so maybe just me but reading "ZNSP" as similar to TI's ZNP, and "ESPZB" as similar to Silabs EZSP (i.e. bellows)