v2.1.6 Duplicate files widget: exclude paths configuration

What's Changed

• [TASK] Improve performance for duplicate files widget by @maikschneider in #19
• [FEATURE] Exclude paths configuration for duplicate files widget by @maikschneider and @ulrichmathes in #21
• [BUGFIX] harden BrokenLinksWidget DI against missing linkvalidator by @ulrichmathes in #22

New Contributors

• @maikschneider made their first contribution in #19

Full Changelog: v2.1.5...v2.1.6