[driver] Ili9341 support Resumable Functions

[TomSaw]

To sweep the yard for #665 , here's an as good as possible pealed out update on ILI9341.
Let's concentrate on the implementation of the Resumables for now.
Drawing functions and a lot more will be cured with the coming up graphics API rewrite.

Changes

• Resumable Functions. I could not backport RF for all drawing functions cause was too painfull.
• optimized drawing functions for Ili9341. The clipping-feature is your friend for squary shapes!
• clear() now also takes a color to clear with: clear(Rgb565 color)
• Dropped backgroundColor. Renamed foregroundColor -> color. To fullfill this change, clear(Rgb565 color) needs to become sooper fast and resource unhungry. A concept witch gets final grip with the coming up graphics API rewrite ;)
• set(Toggle toggle, bool value) substitutes lots of xyzOn(), xyzOff() methods.
• set(ReadWrite reg, uint8_t value) and get(ReadWrite reg, uint8_t value) substitute lots of setXyz(), getXyz() methods.
• Simplified Ili93441<->Interface implementation. I think modm::Ili9341Spi<Ili9341InterfaceSpi<Spi, Cs, Dc> Reset> reads and explains itself so much better than "simplified" modm::Ili9341Spi<SpiMaster, Cs, Dc, Reset>.
• Removed <..., typename Backlight, ...> from Driver
  • A simple Backlight::setOutput(modm::Gpio::High) subsitutes the Feature. However, sometimes a developer wants more control f.e. backlight PWM-Dimmed or hardwired to VCC so is better to keep the LED out of Ili9341 and not bloat the drivers template arguments.
• Optimized color::Rgb565 for performance reasons.
• Renamed color::BrightnessT -> GrayscaleT (Should be another PR 😬 or is ok ?)

ToDo

• Update examples

[salkinium]

Can this be closed in favor of #665?

[TomSaw]

Jupp.