Emitting docs for microzig

[tact1m4n3]

Emitting docs for microzig

Issue for tracking microzig docs. Please feel free to add more things that you feel microzig is curently lacking in terms of documentation.

• [x] Emitting zig docs for firmware (for everything in the app and in microzig)
• [ ] Emitting zig docs for everything microzig (core, drivers, ports). These could also be published to the website.
  • ~~perhaps this can be done using a dummy firmware (maybe having a long introductory comment) and Firmware.get_emitted_docs()~~ this works only for one port/target
• [ ] Update and move docs/design.md to the website
• [ ] Website build system documentation (including what ports are available)
• [ ] Website tour of microzig

** Some hals have the hal.zig file moved outside of the hal directory. This messes with the generation of docs and creates strange names like hal.hal.clocks. Moving hal.zig (the root source file of the hal) inside the hal directory gets rid of this issue.