Support for TCA8418 Keyboard Matrix and IO Expander

[Oekel]

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

I would appreciate an integration for the TCA8418. An I2C Keyboard Matrix and IO Expander.

Adafruit has a library which may help in some way: https://github.com/adafruit/Adafruit_TCA8418.

Here's the info page for their module: https://www.adafruit.com/product/4918

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

I have a device using an ESP8266 with a TCA8418 connected to a 4x4 keypad matrix and want to send these 16 charakters over MQTT

(I know that is is a 1:1 feature-request to: esphome/feature-requests#2474
But maybee this time Tasmota is quicker than esphome ;)