Replace default route part 1

This adds route for most of the missing routes I found via running core cukes and specs.

I tried to change as little as possible in order to break as little as possible. I.e. I didn't split up or rename controller actions even if that was desirable.

See the ticket or the commits for a list:
https://www.openproject.org/work_packages/4996

**Note:** Before merging this, we should make sure this works with all plugins.