Cleanup Code

Remove unneeded stuff and make the codebase more manageable

• Replace use of list.h with zephyr dlist: !18 (merged)
• Remove qsort.h. Zephyr already provides that. (!17 (merged))
• Add clang-format config from upstream and format all files including cmake files. (!16 (merged))
• Remove include/greybus/ara_debug.h. Use zephyr debug infra directly. (!19)
• Remove include/greybus/types.h.