Figure out a structure for all the utskott of Bleckhornen

Bleckhornen has lodsa utskott. It would be nice to formalize this on the website.

Specifications (for now):
* Corpsii must be able to be members of multiple utskott at once.
* There should be a way to assign a leader (ordförande/ansvarig) for an utskott. This should preferably also tie into the contact page, so that people can see the leaders for all available utskott. An idea is to have contact info (like telephone number) tied to a "leader entry", e.g. a table `CommitteeLeader` with columns `corpsId`, `committeeId`, and `telNr`.
* Leaders of an utskott should be able to add and remove corps from their utskott (but only their own!).
* This structure should tie into the permissions on the website, i.e. if you are a member of the board you should have admin access, if you are a member of sexet you should be able to see peoples food preferences, members of ITK get world domination etc.

まず、ウェブサイトに既存のメンバー、連絡先ページ、権限の構造を確認します。複数のutskottへの所属、リーダーの割り当て、リーダーが管理する所属変更、連絡先情報、ロールベースのアクセスに関する要件を整理します。完了とは、指定された委員会および権限のすべての動作がサポートされていることを意味します。

索引モデルが issue の本文から書いたものです。