Search Improvements by Xon 2.17.4

A collection of improvements to XF's Enhanced Search and some for XenForo's default MySQL search.

MySQL & Elastic Search features;

• range_query search DSL
  • allows arbitrary range queries for numerical data
• Allow users to select the default search order independent for the forum wide setting.
  • Re-adds the global option for the default search type

Elastic Search Only features:

• Per content type weighting
• Adds Elastic Search information to the AdminCP home screen.
• Adds a debug option to log the search DSL queries to error log for troubleshooting
• Option to extend search syntax to permit;
  • + signifies AND operation
  • | signifies OR operation
  • - negates a single token
  • " wraps a number of tokens to signify a phrase for searching
  • * at the end of a term signifies a prefix query
  • ( and ) signify precedence
  • ~N after a word signifies edit distance (fuzziness)
  • ~N after a phrase signifies slop amount
  • In order to search for any of these special characters, they will need to be escaped with \.