Resolve "Add export functionality to absence statistics page"

Closes #267

See merge request !477

Fix directory structure for print files

See merge request !478

Merge branch '300-allow-using-time-slot-numbers-in-long-term-absences-dialog-instead-of-datetimes' into 'master'

Resolve "Allow using time slot numbers in long term absences dialog (instead of datetimes)"

Closes #300

See merge request !464

Merge branch 'master' into 300-allow-using-time-slot-numbers-in-long-term-absences-dialog-instead-of-datetimes

Resolve "Not storing groups for documentations is kind of a problem"

Closes #351

See merge request !476

Update .dev-js/package.json

See merge request !474

Update .dev-js/.eslintrc.js

See merge request !473

Use hash of person overview instead of own URL for statistics

See merge request !470

Update tox.ini

See merge request !471

Delete .eslintrc.js

See merge request !475

Update .gitignore

See merge request !472

Did not make a difference. But now it's proper anyhow.