Expose full certificate RFC 4514 Distinguished Name string

Using rfc4514_string() method added in cryptography version 2.5.

lemur/certificates/models.py

@@ -227,6 +227,10 @@ class Certificate(db.Model):
     def location(self):
         return defaults.location(self.parsed_cert)
 
+    @property
+    def distinguished_name(self):
+        return self.parsed_cert.subject.rfc4514_string()
+
     @property
     def key_type(self):
         if isinstance(self.parsed_cert.public_key(), rsa.RSAPublicKey):

lemur/certificates/schemas.py

@@ -206,6 +206,7 @@ class CertificateOutputSchema(LemurOutputSchema):
 
     cn = fields.String()
     common_name = fields.String(attribute='cn')
+    distinguished_name = fields.String()
 
     not_after = fields.DateTime()
     validity_end = ArrowDateTime(attribute='not_after')