[WIP] Add basic CMake implementation

[macuser47]

Description

WIP - DO NOT MERGE

Adds cmake build system. Project is now organized into libraries (app, data, drivers, peripherals, middleware), and executables (main, examples, utils).

At the moment this is just a barely working implementation - it builds everything at once
with no configurability.

Notes

• No changes to the project structure have been made. Currently this means the source files in embedded/app/src are in their own library called app. Do we want to do some restructuring to change this?

TODO

• Successfully compile all code and examples with CMake
• Implement cross-compilation
• Add utility commands like scp deploy
• Write some nice documentation for how to use CMake
• Look into GTest integration (CI?)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings or errors
• I have added tests/examples that prove my fix is effective or that my feature works
• New and existing tests/examples pass with my changes

[rdaruwala]

Wonderful job getting this done!