feat(playlists): drag rows onto a list in the rail

A row's grip carries it, or every selected row with a selected one, onto another
list, under a sort or a filter too, and the toast undoes. The rail and the page
are separate React trees, so the page reads the rail by what lies under the
pointer. An unpinned rail peeks by the drag's own hover and scrolls at its edges.
Many rows dropped inside the list stay; a key still moves its own row.

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

@@ -122,6 +122,11 @@
   "undoMoveFailed": "Couldn't move the video back",
   "undoMoveManyFailed": "Couldn't move the videos back",
   "undoRemoveManyFailed": "Couldn't put the videos back",
+  "dragHandleToList": "Drag “{{title}}” onto a list",
+  "dragPickedMany_one": "{{count}} video picked up",
+  "dragPickedMany_other": "{{count}} videos picked up",
+  "dragOverList": "Over “{{name}}”",
+  "dragDroppedOnList": "Dropped on “{{name}}”",
   "dragBlockedSort": "Reordering by hand is off while a column sort or grouping is applied.",
   "dragBlockedFilter": "Reordering by hand is off while a filter is applied.",
   "clearView": "Reset view",

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

@@ -122,6 +122,11 @@
   "undoMoveFailed": "Nem sikerült visszahelyezni a videót",
   "undoMoveManyFailed": "Nem sikerült visszahelyezni a videókat",
   "undoRemoveManyFailed": "Nem sikerült visszatenni a videókat",
+  "dragHandleToList": "„{{title}}” húzása egy listára",
+  "dragPickedMany_one": "{{count}} videó felvéve",
+  "dragPickedMany_other": "{{count}} videó felvéve",
+  "dragOverList": "A(z) „{{name}}” lista fölött",
+  "dragDroppedOnList": "Letéve a(z) „{{name}}” listára",
   "dragBlockedSort": "A kézi átrendezés ki van kapcsolva, amíg oszloprendezés vagy csoportosítás van érvényben.",
   "dragBlockedFilter": "A kézi átrendezés ki van kapcsolva, amíg szűrő van érvényben.",
   "clearView": "Nézet visszaállítása",