Fix DATE comparisons in NXQL

NXQL it's not managing properly DATE comparisons

Steps to reproduce:

• Set the expiration date of a document to "2018-12-07T23:00:00.000Z"

  "dc:expired": "2018-12-07T23:00:00.000Z",

• Browse to ADMINISTRATION > NXQL Search menu
• Introduce this NXQL sentence and click on Search

  SELECT * FROM Document 
     WHERE 
        ecm:mixinType != 'HiddenInNavigation' 
        AND ecm:isProxy = 0 
        AND ecm:isVersion = 0 
        AND ecm:isTrashed= 0 
        AND dc:expired = DATE '2018-12-07'
  

No results are returned.

You must use a date range to find the documents of a given date to find the document:

SELECT * FROM Document 
   WHERE 
      ecm:mixinType != 'HiddenInNavigation' 
      AND ecm:isProxy = 0 
      AND ecm:isVersion = 0 
      AND ecm:isTrashed= 0 
      AND dc:expired >= DATE '2018-12-07'
      AND dc:expired < DATE '2018-12-08'

Using DATE instead of TIMESTAMP you must be able to find a document for his date without specifying the time