Updated the screenshot for the configuration pages.
Mrge from 2.5 branch: Clean up the admin and doc page styles, update all the screenshot images, and include a link to the MetacatUI Github
FontAwesome and Bootstrap are imported locally rather than via CDN. Updated the docs screenshots to the new style.
Set mime type on images.
edited the configuration docs, swapped in new fully-configured screen shothttp://bugzilla.ecoinformatics.org/show_bug.cgi?id=5516
Moving Metacat Sphinx RST documentation from docs/dev to docs/user directory.
Screenshots from the Metacat admin guide.
