Remove outdated RFC 1068 governance docs.

These docs are very outdated and contains some misleading information.
There are important things to resurrect at some point, which is
something the Council should take on:

* Definition of teams, and the structure of the Project in general:
  rust-lang/leadership-council#33
* Team charters, defining what each team's mission and responsibilities
  are: rust-lang/leadership-council#44
* Suggestions on moderation team processes should follow up with either
  the Council or https://github.com/rust-lang/moderation-team
* Suggested decision making processes for teams:
  rust-lang/leadership-council#45
  (and rust-lang/leadership-council#23 to some
  degree).