Remove Legacy 2 line display

[chris1howell]

In order to provide enhancements in the future for the current ATMEGA328P microprocessor and prepare for porting to ARM processors, legacy and non-safety features must be removed. Enhanced versions of non-safety features exist on the ESP32 WiFi/ LCD.

-Remove legacy 2 line display code
-Remove I2C RGB LED output for display
-Remove button and menu code

[jeremypoulter]

IMHO this shouldn't be removed, there is a significant install base with 2 LCD displays, don't think we want to break support for them. It is also super useful for development. Adding a build option would be better.

[lincomatic]

@jeremypoulter don't worry, I'm not going to remove any of the above code. It can easily be disabled by using different #defines. I'm going to completely deprecate Arduino IDE builds, and rely on different build types for customization