documentation/platforms/arm: Add Nucleo G0B1 board.

Include description of support for Nucleo G0B1RE from STMicro.

Documentation/platforms/arm/stm32g0/boards/nucleo-g0b1re/index.rst

@@ -0,0 +1,57 @@
+================
+ST Nucleo G0B1RE
+================
+.. figure:: nucleo-g0b1re.png
+   :align: center
+
+Board Information
+=================
+
+The Nucleo G0B1RE is a member of the Nucleo-64 board family, based on the
+MB1360 reference board, featuring the STM32G0B1RET6U MCU. The STM32G0B1RE is
+a 64 MHz Cortex-M0+ architecture with 512 KByte Flash memory (Dual bank) and
+144 KByte SRAM.
+
+The board features:
+
+- On-board ST-LINK/V2-1 debugger/programmer
+- 1 user LED
+- User and reset push-buttons
+- 32.768 kHz crystal oscillator
+- Board connectors:
+  - ARDUINO Uno V3 expansion connector
+  - ST morpho extension
+
+Refer to http://www.st.com and UM2324 for further information about this
+board.
+
+Serial Console
+==============
+
+The default console is the virtual serial console through ST-LINK:
+
+1. Nucleo Virtual Console
+
+   The virtual console uses serial port 2 (UART2) with TX on PA2 and RX on
+   PA3.
+
+      ================ ===
+      VCOM Signal      Pin
+      ================ ===
+      SERIAL_RX        PA3
+      SERIAL_TX        PA2
+      ================ ===
+    
+   These signals are internally connected to the on board ST-Link.
+
+   The Nucleo virtual console is the default serial console on all
+   configurations unless stated otherwise in configuration description.
+
+Configurations
+==============
+
+nsh:
+----
+
+This configuration provides a basic NuttShell configuration (NSH) on the
+Nucleo virtual console (VCOM on UART2).