rp2/boards/W5100S_EVB_PICO: Add Wiznet W5100S-EVB-Pico board.

Signed-off-by: Andrew Leech <andrew@alelec.net>

ports/rp2/boards/W5100S_EVB_PICO/board.json

+{
+    "deploy": [
+        "../deploy.md"
+    ],
+    "docs": "",
+    "features": [
+        "Breadboard Friendly",
+        "Castellated Pads",
+        "Ethernet",
+        "Micro USB"
+    ],
+    "images": [
+        "W5100S-EVB-Pico.jpg"
+    ],
+    "mcu": "rp2040",
+    "product": "Wiznet W5100S-EVB-Pico",
+    "thumbnail": "",
+    "url": "https://www.wiznet.io/product-item/w5100s-evb-pico/",
+    "vendor": "Wiznet"
+}

ports/rp2/boards/W5100S_EVB_PICO/mpconfigboard.cmake

+# cmake file for Wiznet W5100S-EVB-Pico.
+set(PICO_BOARD pico)
+set(MICROPY_PY_WIZNET5K W5100S)
+set(MICROPY_PY_LWIP 1)

ports/rp2/boards/W5100S_EVB_PICO/mpconfigboard.h

+// Board config for Wiznet W5100S-EVB-Pico.
+
+// Board and hardware specific configuration
+#define MICROPY_HW_BOARD_NAME             "W5100S-EVB-Pico"
+#define MICROPY_HW_FLASH_STORAGE_BYTES    (1408 * 1024)
+
+// Enable networking and sockets.
+#define MICROPY_PY_NETWORK                (1)
+#define MICROPY_PY_USOCKET                (1)
+#define MICROPY_PY_USSL                   (1)
+
+// Wiznet HW config.
+#define MICROPY_HW_WIZNET_SPI_ID          (0)
+#define MICROPY_HW_WIZNET_SPI_BAUDRATE    (20 * 1000 * 1000)
+#define MICROPY_HW_WIZNET_SPI_SCK         (18)
+#define MICROPY_HW_WIZNET_SPI_MOSI        (19)
+#define MICROPY_HW_WIZNET_SPI_MISO        (16)
+#define MICROPY_HW_WIZNET_PIN_CS          (17)
+#define MICROPY_HW_WIZNET_PIN_RST         (20)
+// Connecting the INTN pin enables RECV interrupt handling of incoming data.
+#define MICROPY_HW_WIZNET_PIN_INTN        (21)

ports/rp2/boards/W5100S_EVB_PICO/readme.md

+# Wiznet W5100S-EVB-Pico
+
+## Network Example
+
+To use network / socket based code, connect ethernet port to network with DHCP running:
+
+```
+>>> import network
+>>> nic = network.WIZNET5K()
+>>> nic.ifconfig()
+('192.168.0.18', '255.255.255.0', '192.168.0.1', '8.8.8.8')
+>>> nic.dhcp(True)
+('192.168.0.10', '255.255.255.0', '192.168.0.1', '192.168.0.1')
+```
+At this point standard network communications libraries should work.