shields: Add arduino uno click shield

The shield converts Arduino UNO R3 headers to two mikroBUS
sockets.
Two mickoBUS sockets are exposed via the overlay labelled
mikrobus_header_1 and mikrobus_header_2.

Signed-off-by: Andriy Gelman <andriy.gelman@gmail.com>

boards/shields/arduino_uno_click/Kconfig.shield

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+# Copyright (c) 2023 Andriy Gelman
+# SPDX-License-Identifier: Apache-2.0
+
+config ARDUINO_UNO_CLICK
+	def_bool $(shields_list_contains,arduino_uno_click)

boards/shields/arduino_uno_click/arduino_uno_click.overlay

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+/*
+ * Copyright (c) 2023 Andriy Gelman
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	mikrobus_header_1: mikrobus-connector-1 {
+		compatible = "mikro-bus";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map =	<0 0 &arduino_header 0 0>,	/* AN   -> A0  */
+				<1 0 &arduino_header 3 0>,	/* RST  -> A3  */
+				<2 0 &arduino_header 16 0>,	/* CS   -> D10 */
+				<3 0 &arduino_header 19 0>,	/* SCK  -> D13 */
+				<4 0 &arduino_header 18 0>,	/* MISO -> D12 */
+				<5 0 &arduino_header 17 0>,	/* MOSI -> D11 */
+								/* +3.3V */
+								/* GND */
+				<6 0 &arduino_header 12 0>,	/* PWM  -> D6  */
+				<7 0 &arduino_header 8 0>,	/* INT  -> D2  */
+				<8 0 &arduino_header 6 0>,	/* RX   -> D0  */
+				<9 0 &arduino_header 7 0>,	/* TX   -> D1  */
+				<10 0 &arduino_header 5 0>,	/* SCL  -> A5  */
+				<11 0 &arduino_header 4 0>;	/* SDA  -> A4  */
+								/* +5V */
+								/* GND */
+	};
+
+	mikrobus_header_2: mikrobus-connector-2 {
+		compatible = "mikro-bus";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map =	<0 0 &arduino_header 1 0>,	/* AN   -> A1  */
+				<1 0 &arduino_header 2 0>,	/* RST  -> A2  */
+				<2 0 &arduino_header 15 0>,	/* CS   -> D9 */
+				<3 0 &arduino_header 19 0>,	/* SCK  -> D13 */
+				<4 0 &arduino_header 18 0>,	/* MISO -> D12 */
+				<5 0 &arduino_header 17 0>,	/* MOSI -> D11 */
+								/* +3.3V */
+								/* GND */
+				<6 0 &arduino_header 11 0>,	/* PWM  -> D5  */
+				<7 0 &arduino_header 9 0>,	/* INT  -> D3  */
+				<8 0 &arduino_header 6 0>,	/* RX   -> D0  */
+				<9 0 &arduino_header 7 0>,	/* TX   -> D1  */
+				<10 0 &arduino_header 5 0>,	/* SCL  -> A5  */
+				<11 0 &arduino_header 4 0>;	/* SDA  -> A4  */
+								/* +5V */
+								/* GND */
+	};
+};
+
+mikrobus_spi: &arduino_spi {};
+mikrobus_serial: &arduino_serial {};
+mikrobus_i2c: &arduino_i2c {};

boards/shields/arduino_uno_click/doc/index.rst

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+.. _arduino_uno_click:
+
+Arduino UNO click shield
+########################
+
+Overview
+********
+
+The Arduino UNO click is an extension to the Arduino UNO R3 headers.
+It's a simple shield that converts Arduino UNO R3 headers to two mikroBUS
+host sockets that allow you to connect many other click shields to your
+board.
+In other words, he Arduino UNO click will generally be used by other
+shields using the mikroBUS interface.
+
+Two mikroBUS headers are exposed by the overlay: mikrobus_headers_1 and
+mikrobus_headers_2, each corresponding to a socket on the Arduino UNO
+click shield.
+
+More information about the shield can be found at
+`Arduino UNO click shield website`_.
+
+Requirements
+************
+
+This shield can only be used with a board which provides a configuration
+for Arduino R3 connector.
+
+Since the Arduino UNO click has two sockets, the user must create a node
+alias depeding on which of the sockets is used:
+
+mikrobus_header: &mikrobus_header_1 {}; or
+mikrobus_header: &mikrobus_header_2 {};
+
+The board must also define node aliases for arduino Serial,
+SPI and I2C interfaces (see :ref:`shields` for more details).
+
+If a node alias for one of the interfaces does not exist and it is not used
+by the connecting shield, a dummy node alias can be created by the board.
+An alternative is to simply delete the node alias from the
+arduino_uno_click.overlay file. For example if a connecting shield only uses
+the mikrobus_spi node alias, then mikrobus_serial and mikrobus_i2c can be deleted.
+
+Programming
+***********
+
+Include ``-DSHIELD=arduino_uno_click`` when you invoke ``west build`` with
+other mikroBUS shields. For example:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/can/counter
+   :board: xmc47_relax_kit
+   :shield: "arduino_uno_click mcp2518fd_click"
+   :goals: build
+
+References
+**********
+
+.. target-notes::
+
+.. _Arduino UNO click shield website:
+   https://www.mikroe.com/arduino-uno-click-shield