SAML auth improvements

[olivierlambert]

Origin: Ticket#7724744

• Add an option to import IDP metadata
  • Ideally you just point the saml service to the IDP metadata xml file to automatically populate and correlate the info to the appropriate fields
• Download the SP metadata
  • This is a reverse file hosted on the client that the IDP would point to to automatically populate and correlate the info to the appropriate fields
• Add the ability to change NameID format
• Add the ability to choose binding (redirect is preferred to post)