[MCU] Document structure for hardware driver modules

[AndreasFreund]

User story

1. As a developer of hardware drivers / C modules
2. I want / need a clear structure
3. So that I can easily navigate my and others modules

Acceptance criteria

• Agree on file naming scheme for generic (platform independent) vs implementation (platform specific) headers and source files
• Agree on naming for functions

Definition of done (DoD)

• Added only after week 5
• The same for all features
• Here goes the project specific part

DoD general criteria

• Feature has been fully implemented
• Feature has been merged into the mainline
• All acceptance criteria were met
• Product owner approved features
• All tests are passing
• Developers agreed to release