Authenticate a client in case of IdP-initiated Single Sign-On (SSO)
TElSAMLIdentityProvider.AllowIDPSSO property should be enabled. A few URLs on IdP may be used to initiate SSO. Each URL must be described by TElSAMLIdPSSOLink instance added to configuration using TElSAMLIdentityProvider.AddIdPSSOLink() method. TElSAMLIdPSSOLink.URL property defines a relative URL, TElSAMLIdPSSOLink.RelayState property defines optional relay state to be transferred to SP, TElSAMLIdPSSOLink.SPIndex is an index of SP configuration to be used from the list of available configurations stored in TElSAMLIdentityProvider.ServiceProviders property.