FR: Allow specifying metadata directly in DSL

[ttomsu]

I currently see 3 pieces of key information pulled out of the metadata.xml file:

1. entityID
2. x509 certificate
3. redirect SSO URL

I'd like to be able to specify these directly, rather than mess with an HTTP or file-based way.

[jeanbza]

This may require some rewrites to the underlying spring security SAML library, but would be a really good feature to have.

[markdouglasswork]

Agreed on all fronts.