Make configuration API only available to jury and limit submissions output to valid ones.

The amount of info available through the configuration variables may not
be stellar, but it's not always published in another form, so limit access
to prevent surprises.

For submissions, it makes sense not to include invalidated submissions
by default. If someone has a usecase for getting those, we can add an extra
query parameter.
Update to reflect ICPC webservice changes
Publish standings to ICPC from jury scorecache.

You will always want to publish the final standings, never the frozen ones.
Fixes #146
Prevent mistaken standings upload while contest still running.

Fixes #146
Need to get ranks from jury point of view.

Thanks @baierjan for noticing.