Light parameters to use on bootup

**Describe the problem you have/What new integration you would like**

When the light component is set to turn on upon bootup (eg ALWAYS_ON, RESTORE_DEFAULT_ON, etc), it turns on with maximum brightness, etc.

What would be good if the brightness, color_temp, etc parameters can be configured, so that when the light is turned upon bootup, it uses the configured parameters. The reason for this is some of my lights are much too bright and is the wrong color_temp for my liking. I am setting the lights to turn on upon bootup for the scenario that HA is not available/WiFi down, but I want the lights to continue to work via the wall light switch.

**Please describe your use case for this integration and alternatives you've tried:**

I've tried adjusting the light parameters with different on_boot priorities, but never got it working seamlessly (sometimes delay too long, etc, so the light still turns on with max brightness and the default color_temp, then changes to my preferred parameters after a delay). I managed to do this with tasmota so that the lights first turns on at the desired parameters, but I really want to go back to esphome.

**Additional context**

The request names no files, tests, or entry points. Start by locating ESPHome's light bootup handling and the existing on_boot behavior; done would mean configurable brightness and color temperature are applied at boot without a later corrective delay.

Written by the indexing model from the issue text.