Add Per-Light Settings for Maximum Brightness Adjustment

[eqxDev]

This update introduces a new configuration option called Light Settings. It allows users to set a maximum brightness percentage for individual lights based on their serial numbers.

Details:

• Configuration:
  • The Light Settings option accepts an array of objects, each containing:
    • serialNumber: The unique serial number of the light.
    • limit: The maximum brightness percentage (1-100%).
  • Brightness is dynamically adjusted in HomeKit based on the defined limit.
• Example Behavior:
  • If a light has a maximum brightness limit of 70%:
    • Setting HomeKit brightness to 100% adjusts the light to 70%.
    • Setting HomeKit brightness to 50% adjusts the light to 35%.

Use Case:
This feature is particularly useful for scenarios where certain lights have power or brightness constraints. For instance:

A Philips light on an oven hood with a 4W limit can be safely used by setting its maximum brightness to 70%.
Example Configuration:

"lightSettings": [
  {
    "serialNumber": "001788102201",
    "limit": 70
  },
  {
    "serialNumber": "001788102202",
    "limit": 50
  }
]

Why This Change?
This enhancement provides finer control over individual lights, improving both usability and safety. It ensures that lights with specific hardware limitations can function optimally without manual intervention.

[ebaauw]

I'm sorry, I won't be merging this PR into Homebridge Hue, for the reasons listed below. Of course, you're more than welcome to run this update in your environment.

1. I've frozen development of Homebridge Hue and no longer implement new features, see Future Development of Homebridge Hue #1070 (comment).
2. Even before the development freeze, I wouldn't maintain config.json settings for individual devices. This is very complicated and prone to a lot of support questions. I will support settings for individual devices in Homebridge Hue2, similar to the dynamic configuration in Homebridge deCONZ.
3. Functionally, I have doubts whether the maximum brightness setting should be implemented in a Homebridge plugin. It should be a device feature. I think it's misleading to call this a safety feature. As Homebridge adds HomeKit functionality to existing devices, there's no guarantee that these devices are controlled exclusively through HomeKit. I suppose you could monitor the brightness setting, and automatically adjust it when it would exceed the limit. However this is a home automation feature, beyond the scope of a Homebridge plugin. In my view, Homebridge plugins expose devices to HomeKit, sticking as much as possible to the native device features.