MDQ support for InCommon metadata consumption in Gluu server

[mzico]

InCommon has introduced MDQ for their metadata query lately, It will greatly help us to manage server resources.

There are two parts in this development:

• Backend
• FrontEnd

When we are done with this issue [ backend part ], we will open a new github issue under oxTrust to allow GUI for Gluu Server administrator so they will be able to manage this from Gluu admin panel.

Here are docs:

• https://spaces.at.internet2.edu/display/mdq
• https://spaces.at.internet2.edu/display/MDQ/Configure+Shibboleth+identity+provider

[mzico]

@uprightech : we have a real scenario in one production server which require MDQ support to be enabled.