Upgrade jquery version installed with skeleton to latest version

3.x license: https://raw.githubusercontent.com/jquery/jquery/3.x-stable/LICENSE.txt

The Essentials LICENSE file contains the line ' This version of jQuery includes Sizzle.js, which is also released under the MIT License.', no reference to this statement found in current jQuery releases so assuming no explicit reference is needed using a direct copy of the jquery distribution

Skeleton jQuery is used in the following places

• FAQ plugin:  used in the harmonica variant using Bootstrap
• Open Street Map: When using an address uses jQuery getJSON to request a address lookup and fetch the json results
• Banner carrousel for rotating the images using Bootstrap

Initial testing found no issues with updated jQuery. Open Street Map address lookup sometimes out both in both the old and new version of jQuery