Add structure type "journal" and handle it like newspaper or ephemera in calendar plugin

[albig]

Description

The calendar plugin currently only works with structure type newspaper or ephemera.

To use the same structure for journals as requested in https://github.com/slub/dfg-viewer/issues/175, Kitodo.Presentation must accept journal in the documenType switch.

The calendar should always be used for:

newspaper | ephemera | journal -> year -> month -> issue