[BUG:T13] Hide translation not correctly processed

[dkd-kaehm]

Issues in this process:

• Integration-test GarbageCollectorTest::queueItemStaysWhenOverlayIsSetToHidden does not test that really
  Even if test is successful, in BE the index queue item was removed
• The process is currently wrong on changing translated page to "hide":
  1. removes the Translation from Index (OK)
  2. does not remove the index queue item for original page (OK)
  3. does not queue the index queue item for indexing (BUG)
     This leads to missing index for translation if "fallback"-mode is active(until the origianal page is changed or Re-Index is triggered)

Each action MUST queue the "index queue item" (set tx_solr_indexqueue_item.indexed = 0), to go through whole EXT:solr processing.