[FEATURE] Seamless document browsing

[michaelkubina]

This PR adds a feature to the navigation controller, that allows navigating to the prev/next document (volume/issue/etc) relative to the currently one viewed. It implements backtracking, so that it allows for overflowing to the next leafe node if necesseary, e.g. from the last newspaper issue of the current year to the first issue of the next year (and back). Since the backtracking is recursive, this allows backtracking any depths which will very well be necessary for complex document trees from Kalliope (inventories with subinventories with subinventories etc.).

This addresses the following issue: #760

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (3e140e0) to head (f0c026a).
Report is 1 commits behind head on main.

Additional details and impacted files

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