Add block diagram to bare_metal.md

Add block diagram image to bare metal profile overview page to fill gap in content.

Author: Amanda Butler

docs/bare_metal.md

@@ -2,6 +2,8 @@
 
 There are many use cases for IoT devices. Different use cases require different configurations, connectivity and security. These different use cases also have different requirements for resource consumption. Many IoT use cases that need to operate in ultraconstrained environments on tiny MCUs with low memory and compute power available. We created the Mbed OS bare metal profile for IoT device use cases on ultraconstrained resources.
 
+<span class="images">![Mbed OS bare metal profile block diagram](https://raw.githubusercontent.com/ARMmbed/mbed-os-5-docs/development/docs/images/bare_metal_block_diagram.png)<span>Mbed OS bare metal profile block digram</span></span>
+
 The Mbed OS bare metal profile is a compact profile of Mbed OS 5 without an RTOS. The Mbed OS bare metal profile is API compatible with Mbed OS 5 and supports a subset of features of Mbed OS 5, such as analog I/O, digital I/O, timers and digital interfaces, such as SPI, I2C, Serial and CAN. Mbed Studio, Mbed CLI and the Mbed Online Compiler all support the Mbed OS bare metal profile.
 
 To begin using the Mbed OS bare metal profile from Mbed OS 2, please follow our [instructions](../tutorials/migrating-to-mbed-os-5.html).