Option to override IDP entityID
Some federation systems do not allow that SP and IDP modules share the same entityID. This is the case in Renater.
We could add an option to override the entityID of the IDP and set this value in authn responses, like we do for Office 365 with the domain parameter.
Sadly we can't use the ?domain=test trick with Renater, the special characters are not allowed in URL. So we should have for example this entityID for SP: https://auth.example.com/saml/metadata and this entityID for IDP : https://auth.example.com/saml/idp-metadata