lcd_hd44780: Make the row offsets array static const.
lcd_hd44780: Get rid of some unnecessary delays in the 4-bit interface.

There is no need to wait for 50 us between nibble writes and reads.
lcd_hd44780: Use consistent naming: pulseEnable -> pulse_enable, setRS -> set_RS.
lcd_hd44780: Move LCD_4BITMODE out of FourBitLCDInterface.
lcd_hd44780: Convert #defines to static constexprs.