Support importing SAML metadata xml to configure SSO

[knolleary]

Description

To setup SAML SSO requires three pieces of configuration from the IdentityProvider; the entityID, the SSO url and the public certificate.

Whilst these can be individually copied into the configuration, there is a standard XML metadata format that many IdPs provide that includes this information.

It would be a small paper-cut improvement to support importing this metadata when setting up an SSO configuration.

Here's an example from OKTA:

<md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" entityID="http://www.example.com/secret/id">
   <md:IDPSSODescriptor WantAuthnRequestsSigned="false" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
      <md:KeyDescriptor use="signing">
         <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
            <ds:X509Data>
               <ds:X509Certificate>... a certificate ... </ds:X509Certificate>
            </ds:X509Data>
         </ds:KeyInfo>
      </md:KeyDescriptor>
      <md:NameIDFormat>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</md:NameIDFormat>
      <md:SingleSignOnService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://example.com/secret/sso/saml"/>
      <md:SingleSignOnService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect" Location="https://example.com/secret/sso/saml"/>
   </md:IDPSSODescriptor>
</md:EntityDescriptor>

Which customers would this be available to

Enterprise Tier Only (EE)

Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate