Correctly handle archives being part of multiple RSS feeds (see #7398)
Merge branch 'hotfix/3.2.16' into release/3.4.0

Conflicts:
	assets/contao/js/core.js
	system/docs/CHANGELOG.md
	system/modules/core/classes/Frontend.php
	system/modules/core/widgets/MetaWizard.php
Add an empty option to the image size select menu (see #7436)
Add the CSS units `vw`, `vh`, `vmin` and `vmax` (see #7417)
Consider image size IDs when overriding the default image size (see #7470)