feat(filters): pick one year from a decade grid, in the feed and in Plex

A shared YearPicker: the recent years as chips with their counts, and a
More dialog that lays every year out by decade (sortable by count), so a
ninety-year library fits on one screen. The feed's scrolling popover gives
way to it; the Plex rail gets it above its range fields, a pick setting
both ends. The Plex facets now count titles per year, the year filter left
out.

frontend/src/i18n/locales/en/sidebar.json

@@ -36,6 +36,7 @@
   "year": {
     "more": "More",
     "moreLabel": "All years",
+    "decade": "{{from}}–{{to}}",
     "none": "No years yet",
     "sortBy": "Sort",
     "sortYear": "Year",

frontend/src/i18n/locales/hu/sidebar.json

@@ -36,6 +36,7 @@
   "year": {
     "more": "Több",
     "moreLabel": "Összes év",
+    "decade": "{{from}}–{{to}}",
     "none": "Még nincs év",
     "sortBy": "Rendezés",
     "sortYear": "Év",