White Blend Mode RGBW Light

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

I want to use White and RGB Channels all at the same time to replace Tasmota with ESPHome.
Tasmota has a feature to mix White and RGB Channels to create brighter colors and also the brightest white automatically.
It's called White Blend Mode.
There is the Mix Mode here in ESPHome for Warm and Cold White which seems to be similar but only for White colors.
But it's not possible to use it with RGB Color together as one Color Control.

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

It would be great to have the White Blend Mode Feature available in ESPHome so we don't have to control the White Channel individually all the time.

**Additional context**

Tasmota Feature Reference: [White Blend Mode](https://tasmota.github.io/docs/White-Blend-Mode/)

Start by reading the linked Tasmota White Blend Mode reference and comparing it with ESPHome's existing Mix Mode for warm and cold white. Define how RGB and white channels should be controlled as one color control, including brighter colors and automatic brightest white; the feature is done when this behavior is available without individually controlling the white channel.

Written by the indexing model from the issue text.