v2 - SP metadata - NameID should be configurable

[fhanik]

Support a list of NameID URNs through configuration

Acceptance:

spring:
  security:
    saml2:
      service-provider:
        name-ids:
          - urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified
          - urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress
          - urn:oasis:names:tc:SAML:2.0:nameid-format:transient

When viewing metadata, these three NameIDs should be present, no more, no less