Fix null packet handling in the PIC32 USB device driver.  This is a critical bug fix for PIC32.  Add support for the USB monitor to the Sure-PIC32MX configuration

Converted all configurations to use the kconfig-frontends tools, cleaned up the directory structure and naming to match some of the more recent configurations, and added a segment LCD driver for the board.  The initial checkin of the LCD driver is just a clone of configs/pcblogic-pic32mx/src/pic32mx_lcd1602 and it not yet expected to be functional.

Add apps/examples/slcd, Remove USB from STM32L-Discovery, LSE support for the STM32 L family, some STM32L-Discovery LCD debug changes

Fix STM32L15X vector definitions; Fix STM32L-Discovery LED controls.  The NSH configuration is now fully functional on the STM32L-Discovery board.

Useless TIOCSERGSTRUCT logic in most serial drivers is not compiled unless CONFIG_DEBUG and CONFIG_SERIAL_TIOCSERGSTRUCT are defined

Various Kconfig files still have references to CONFIG_ variables.  Some in harmless comments, some in config definionts which is not harmless.  All removed