tweaks to header section and logo

rebranding

Get rid of custom Shib code & revert to generic Omniauth for everything. Modify identifier_schemes table to add scheme specific urls.

added a initialization helper to assist with omniauth provider registration. Added a remove.png image for disconnecting providers from user accounts

moved assets from app/assets to lib/assets. The files in lib/assets will be used by Rails unless override by an equivalent file in app/assets. Added logic to applicationController so that it will look first for a template in app/views/[:branded folder name] before using the default in app/views