Add support for multiple units that connect with a single wifi controller

[cmroche]

When sending {"t": "scan"} request i got:
{"t":"dev","bc":"","catalog":"gree","series":"gree","model":"gree","lock":0,"vender":"1","mid":"60","name":"GR-Gcloud_60_0a_5ba3_EC","ver":"V3.2.M","mac":"9424b8fd5ba3","subCnt":6}
"subCnt":6 is number of indoor units.

Then sending request to get a list of units:
{"cid":"app","i":0,"pack":"Lmtc+jPqo5okmScSkppBww==","t":"subList","tcid":"9424b8fd5ba3","uid":0}
(pack with empty payload), "t":"subList" is the point.
The responce will be:
{"t":"subList","i":0,"c":6,"r":200,"list":[{"mac":"09c4a41d000000","mid":"6049"},{"mac":"352ea01d000000","mid":"6092"},{"mac":"655ea31d000000","mid":"6049"},{"mac":"0741a01d000000","mid":"6092"},{"mac":"21eda91c000000","mid":"604c"}]}
(Here i have something strange, i have 6 units, but list contain only 5, on phone app i see all 6 units)

And now if i send regular payload, but in "mac" i put internal unit mac adress, it works,
{"cols":["Pow"],"mac":"21eda91c000000","t":"status"}
i successfully got stats, powered on and off, changed temperature.

home-assistant/core#122200

[jgjc222]

Looking forward to this enhancement, thanks 🙏

[meirlo]

I've implemented this in #148.

It follows exactly the protocol described here: gateways are detected via subCnt, sub-devices are enumerated with a subList query, and each indoor unit is then addressed by putting its internal MAC in the pack. Each unit is surfaced as a regular DeviceInfo, so it flows through the existing discovery/device pipeline and can be controlled independently.

The change is library-only and backward-compatible — the Home Assistant integration (home-assistant/core#122200) needs no code changes, just a greeclimate version bump once released. It's tested and verified against a real 4-unit VRF gateway.

Would appreciate a review whenever there's time 🙏 — a number of people have been waiting on this.