Add support for Adafruit HT16K33 based LED displays

**Describe the problem you have/What new integration you would like**
Could you please add support for Adafruit [LED backpack displays](https://learn.adafruit.com/adafruit-led-backpack/featured_products) all based on the HT16K33 I2C chip. Their products include an LED bargraph, LED 8x8 dot matrix (single and multi-color), 7-segment LED, and 4-digit alpha-numeric LED display.

**Please describe your use case for this integration and alternatives you've tried:**
ESPHome currently does not have support for an alpha-numeric LED display which I am most interested in, yes ESPHome has the max7219 platform, and the upcoming TM1637 but they only support 7-segment displays.

**Additional context**
There is an existing [Arduino library](https://github.com/adafruit/Adafruit_LED_Backpack) which supports all the LED backpack types of displays. It is I2C based so should be a relatively simple adaption of the lcd_pcf8574 display platform.