To Tutorial Search: Add full text search and partial word search

Use case:
My GTA experience: when users/attendees experience an issue with a tutorial, they often include a screenshot of the UseGalaxy.* page but do not reference which tutorial they are working on. Need to be able to do a better text search for keywords that appear in their screenshots to prevent a lot of back-and-forth. Right now, it seems the search only works for complete words and on Tags and Tutorial URL content.

Start by reviewing the existing tutorial search behavior for Tags and Tutorial URL content. The work is done when searches can match full text, partial words, and keywords visible in tutorial screenshots, reducing the need for users to identify the tutorial manually.

Written by the indexing model from the issue text.