I2C to UART Bridge (WK2132 / SC16IS750 / MSP430)

**Describe the problem you have/What new integration you would like**
I would like to connect several devices using UART on a remote daughter board to an ESP32. Using an ethernet cable as the connection between the main board and the daughter board limits the number of UARTS to can be used.
A I2C to UART Bridge could solve this issue.

**Please describe your use case for this integration and alternatives you've tried:**
I have an ESP32 in my camper which is connected to several sensors and other devies collecting info and controlling devices. Multiple things are connected using normal I/O ports, I2C bus and also UART. I would like to connect several UART devices which are a bit away from the ESP32 and therefore I designed a daughter board connected with an Ethernet Cable (RJ45).
But the number of UARTs is limited by the number of pins by the cable.
Searching around I found multiple I2C to UART bridges that could solve this problem.

**Additional context**
There are 3 different ICs that I found which could be looked at.
1.) WK2132
This is already build as a module and well documented:
https://wiki.dfrobot.com/Gravity%3A%20IIC%20to%20Dual%20UART%20Module%20SKU%3A%20DFR0627
https://dfimg.dfrobot.com/nobody/wiki/3646cb26e392103672637b458d4995a3.pdf
https://datasheet.lcsc.com/lcsc/1912111437_WEIKAI-WK2132-ISSG_C401039.pdf

1.) NXP SC16IS750
https://www.aliexpress.com/item/32772877194.html
https://www.nxp.com/docs/en/data-sheet/SC16IS740_750_760.pdf

2.) TI MSP430
https://www.ti.com/lit/an/slaa908a/slaa908a.pdf

My favorite I think would be the WK2123 as it features two UARTs and looks like it has a simple support circuit as seen in the schematics from the Gravity Module.

I was thinking if this could be implemented similar to the I/O Expander (https://esphome.io/components/mcp230xx.html) where the new UART buses would then just get new IDs (like the normal UART bus)

No source files, tests, or implementation entry points are named. Start by reviewing the ESPHome I/O Expander pattern and the linked WK2132, SC16IS750, and MSP430 documentation, then define which bridge hardware is supported and how its UART buses receive IDs; done means the proposed integration is implemented and documented.

Written by the indexing model from the issue text.