RFC 43: Streamline the RFC writing process

Streamline the writing and publishing of RFCs by relying on markdown and dedicated spellcheckers and linters.

Rendered version: https://gitlab.archlinux.org/antiz/rfcs/-/blob/streamline_rfc_writing/rfcs/0043-streamline-the-rfc-writing-process.rst



Co-authored-by: David Runge (dvzrv) <dave@sleepmap.de>