esp32/boards: Add new GENERIC_S3 board definition.

Thanks to Seon Rozenblum aka @UnexpectedMaker for the work.
Signed-off-by: Damien George <damien@micropython.org>

ports/esp32/boards/GENERIC_S3/mpconfigboard.cmake

+set(IDF_TARGET esp32s3)
+
+set(SDKCONFIG_DEFAULTS
+    boards/sdkconfig.base
+    boards/sdkconfig.usb
+    boards/GENERIC_S3/sdkconfig.board
+)
+
+if(NOT MICROPY_FROZEN_MANIFEST)
+    set(MICROPY_FROZEN_MANIFEST ${MICROPY_PORT_DIR}/boards/manifest.py)
+endif()

ports/esp32/boards/GENERIC_S3/mpconfigboard.h

+#define MICROPY_HW_BOARD_NAME               "ESP32S3 module"
+#define MICROPY_HW_MCU_NAME                 "ESP32S3"
+
+#define MICROPY_PY_BLUETOOTH                (0)
+#define MICROPY_HW_ENABLE_SDCARD            (0)
+#define MICROPY_PY_MACHINE_DAC              (0)
+
+#define MICROPY_HW_I2C0_SCL                 (9)
+#define MICROPY_HW_I2C0_SDA                 (8)
+
+#define MICROPY_HW_SPI1_MOSI                (35)  // SDO
+#define MICROPY_HW_SPI1_MISO                (37)  // SDI
+#define MICROPY_HW_SPI1_SCK                 (36)

ports/esp32/boards/GENERIC_S3/sdkconfig.board

+CONFIG_FLASHMODE_QIO=y
+CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
+CONFIG_ESPTOOLPY_FLASHSIZE_DETECT=y
+CONFIG_ESPTOOLPY_AFTER_NORESET=y
+
+CONFIG_SPIRAM_MEMTEST=
+
+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
+CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE_16MB=
+CONFIG_PARTITION_TABLE_CUSTOM=y
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-8MiB.csv"