Fix up build_family style builds:

- added back pre-existing board directories which now just select PICO_BOARD
 - added boards/pico_sdk which just uses the pre-existing PICO_BOARD setting
 - fixed rp2040/family.cmake to include the magic string "CFG_TUSB_MCU=OPT_MCU_RP2040" expected by build_family.py

hw/bsp/esp32s3/family.cmake

@@ -6,5 +6,5 @@ include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 set(SUPPORTED_TARGETS esp32s3)
 
 # include basic family CMake functionality
-set(FAMILY_MCUS esp32s3 ESP32S3) # TODO MERGE THIS WITH supported targets?
+set(FAMILY_MCUS ESP32S3)
 include(${CMAKE_CURRENT_LIST_DIR}/../family.cmake)