Add MijnIRMA login credential

pbdf/Issues/mijnirma/description.xml

+<IssueSpecification version="3">
+	<Name>MijnIRMA login</Name>
+	<ShortName>MijnIRMA</ShortName>
+	<SchemeManager>pbdf</SchemeManager>
+	<IssuerID>pbdf</IssuerID>
+	<CredentialID>mijnirma</CredentialID>
+	<Description>
+Your MijnIRMA login.
+	</Description>
+	<ShouldBeSingleton>true</ShouldBeSingleton>
+
+	<Id>1</Id>
+
+	<Attributes>
+		<Attribute>
+			<Name>email</Name>
+			<Description>Your verified email address.</Description>
+		</Attribute>
+	</Attributes>
+</IssueSpecification>