Add configurable locale directory from Aurelien. Nuke ancient compat code.
Add configurable locale directory from Aurelien. Nuke ancient compat code.

lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch