[Search] Improved Search Titles

Added Swiftype meta tag to be used for search titles instead of page titles.

Currently, both search results and search autocomplete display options are like this (searching for "Data"):

"Ember.js - Ember Data"
"Ember.js - Stabilizing Ember Data"
…

Adding Swiftype meta tag to be used instead of page title will essentially remove "Ember.js - " from each matching search title and change the results to this:

"Ember Data"
"Stabilizing Ember Data"
…

__The "st:title" meta tag takes precedence over "title" tag__. More about Swiftype meta tags [here](https://swiftype.com/documentation/meta_tags).