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
Add the screenshots for the password file authentication and ldap authentication.
FontAwesome and Bootstrap are imported locally rather than via CDN. Updated the docs screenshots to the new style.
Set mime type on images.
Moving Metacat Sphinx RST documentation from docs/dev to docs/user directory.
Merged most recent changes from trunk into the RST converted version of the Administrator's Guide. Now the Sphinx/RST version is up to date rlative to the most recent word document, and is now the active copy. The MS Word document will be deprecated and removed. All future changes should be made to the RST version.
