esp32: Merge with master.

esp32/Makefile

esp32/README.md

esp32/application.mk

esp32/boards/LOPY/LOPY_868/script

esp32/boards/LOPY/LOPY_915/script

esp32/boards/LOPY/mpconfigboard.h

esp32/boards/SIPY/SIPY/script

esp32/boards/WIPY/WIPY/script

esp32/hal/esp32_mphal.c

esp32/lib/libbt.a

esp32/lib/libcxx.a

esp32/lib/libdriver.a

esp32/lib/libesp32.a

esp32/lib/libexpat.a

esp32/lib/libfreertos.a

esp32/lib/libjson.a

esp32/lib/liblog.a

esp32/lib/liblwip.a

esp32/lib/libmbedtls.a

esp32/lib/libmicro-ecc.a