Removes team input from volunteer form, link to team page from account page

New research into MongoDB has made me realize that updates on multiple collections cannot be done atomically so they must either be separated into multiple user actions or possible data inconsistencies must be considered. Ask me if you need further explanation about this topic. Or research the lack of transactions in MongoDB.

**Changelog:**

 - Removes `Team Affilation` input from volunteer registration page by removing it from `server/views/volunteer.html`.
 - Adds a link to path `/volunteer/team` to the volunteer account page by adding it to `server/views/volunteer-account.html`.