Guides for running your clan on Elixir Clan

Six new pages in the docs' Clan group: bringing your clan (signing in, your role, the ten-member threshold), the weekly report, standing and the Elder band, actions and the inactivity clock, awards and trophies, and writing the clan's policy with the leaders' pages beside it. Each is written from what Elixir Clan does today. No change to the tools.