Main = Login, separate About page

[massar]

Many portals will just want to have a "Login" page, with a link to an optional About page for not-logged in people.

This allows people who have access to login easily (instead of having to click on the login button) and people who do not have an account to see some details about the portal.

Thus change that / == login and (toggleable) /about/ can show what is currently on /.

Enable Markdown rendering for /about/ while we are at it.