Create a debug RTOS task

[nwdepatie]

This ticket encompasses a pretty sizeable scoped task, where we need to create an RTOS task to print characters to the UART channel that is exposed on the MPU. This will allow us to actually get real time debugging for Cerberus. However, the catch is that we need to create a low priority task that just prints a small amount of characters to the channel, since we don't want to prevent other tasks from running because we are taking a long time to print a fat string.

This ticket encompasses making a queue that contains a varying amount of strings to send over the UART channel, a function/macro that can wrap the queue functionality to make it easy for the developer to print some debug stuff, and also the actual low priority task that will take some characters off the queue and send it out.

[nwdepatie]

I think that this task is linked to #32, as we should get UART printf debugging working first