Enhancement: Clean up directory structure

Product: (OC-SDR, OC-LTE, OC-LTE, OC-Power, others)

Component: (PSU, GBC, BBU, FEM, LED, ME)

Category: (Hardware, Software/stack, Firmware/bootloader, Documentation)

Software/stack

Describe the solution you'd like
Decide on a final directory structure for the firmware source/headers and update the repo to reflect it.
Would we want to go back to the coding guidelines and keep C and header files in the same directory? If so I suggest have a flat "inc/" dir that includes all other misc headers.

Is your feature request related to a problem? Please describe.
Actual repo doesn't reflect stated coding_style_guide for C and header files. Cleaning up (and possibly changing guidelines to match cleanup) for consistency, and maintaining that going forward would make things easier.