Team manual back2tex

[thijskh]

No description provided.

[eldering]

Some general comments that not necessarily should be done in this PR:

• It would be nice if doc/team/gentexconfig.in would fetch some configuration defaults from etc/db-config.yaml or if the system is already installed from a running DOMjudge API.
• I'd make the only make targets under doc/ to be dist, to pre-generate documentation to be shipped in the tarball, no targets that are meant to be run by the admin user installing DOMjudge. I think this makes things clearer and also simplifies the Makefiles.
• For the team manual, we should just provide a script (basically doc/team/genteammanual) that an admin user can run to regenerate the team manual with updated text and/or configuration. But this should be completely outside the Makefile structure.