Add custom board to make it possible to define custom mix of display and touch from code with C functions

[paaspaas00]

You have some nicely-defined boards here. However, people may want to use the library for use with a compatible display (for which there are drivers in this lib) and with this library's touch drivers etc.
To do so people are currently forced to write a custom board definition even if they actually don't have an actual, phisical board, but just a display.
To make stuff easier, would it be possible to provide a nice programming API exposing basically everything it's exposed via compile flags, bit as C/C++ functions? So people can mix and match display, touch etc straight from code, without writing a board.
The board config for this would simply be "esp32_custom"

[paaspaas00]

basically something like #126 for use of functions

[rzeldent]

You can also remove the git-submodule and create your own board (or start with a predefined board) in the boards directory...
This is already possible...

[paaspaas00]

@rzeldent hi, thanks for your reply! Yes I know it's already possible with custom boards, but I meant more of a way to define stuff via software, in C++. Like create a display with some constructor, create a touchscreen with some constructor etc

[rzeldent]

The driver is now written in C, not C++. This would involve quite some changes.
Somewhere in the future this would be something to make classes out of the drivers but for now not a priority...

[paaspaas00]

@rzeldent thank you! I mean, C++ is just easier with classes etc, but no problem, the API could be made available in C as well, no big deal. You could as well expose C APIs