Requesting help for ThinQ v1 air purifier support
<!--
First, You need enable Homebridge debug mode, check debug logging and you can see something like this:
```
[LGThinQ] Found device:  xxx-xxx-xxx-xxx-xxx: Washer (WASHER xxxxxxxx)
```
if device currently not supported, maybe
```
[LGThinQ] Device not supported:  xxx-xxx-xxx-xxx-xxx: Dryer (DRYER xxxxxxxx)
[LGThinQ] device data: *********************
```
-->

**Which device do you want to add? Please describe:**
<!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
LG Air purifier AS128VWA (2018?)

**Describe the solution you'd like:**
<!-- A clear and concise description of what you want to happen. Ex. I want to check my fan is ON/OFF, want to control a rotation speed ... -->
I want basic control support for Fan speed, turning on/off, observe air quality sensor data.

**Device Data:**
<!-- Put a device data in debug log here. -->
> (node:4292) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'type' of undefined
    at DeviceModel.decodeMonitor (/homebridge/node_modules/homebridge-lg-thinq/src/lib/DeviceModel.ts:204:30)
    at Function.transform (/homebridge/node_modules/homebridge-lg-thinq/src/v1/helper.ts:33:47)
    at ThinQ.pollMonitor (/homebridge/node_modules/homebridge-lg-thinq/src/lib/ThinQ.ts:163:21)
    at LGThinQHomebridgePlatform.discoverDevices (/homebridge/node_modules/homebridge-lg-thinq/src/platform.ts:100:51)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at HomebridgeAPI.<anonymous> (/homebridge/node_modules/homebridge-lg-thinq/src/platform.ts:53:7)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:4292) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)
(node:4292) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

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From the Homebridge GUI, it looks like the plugin correctly fetches device data but fails to interpret it dues to the device being an older version of ThinQ (even with ThinQ v1 compatibility option checked). 

I tried making a fork of the older [homebridge-wideq](https://github.com/zvuc/homebridge-wideq/commit/171b006d1a29ca0424c124834042b7caf1057526) to successfully detect the device to at least be able to send ON/OFF control signals, but due to lack of my knowledge I couldn't really make any further progress. It would be really nice if this plugin could also add support for the "legacy legacy" devices. 

I'd be happy to provide any further data if you need them.
