Fix Pylint upgrade issues

* Remove unsupported pylint disable options
    * star-args removed in Pylint 1.4.3
    * abstract-class-little-used removed in Pylint 1.4.3

* Fixes new lint errors

* Copy dummy-variable-rgx expression to new ignored-argument-names expression to ignore unused funtion arguments

* Notable changes
    * Refactor to satisfy Pylint no-else-return warning
    * Fix Pylint inconsistent-return-statements warning
    * Refactor to satisfy consider-iterating-dictionary
    * Remove methods with only super call to satisfy useless-super-delegation
    * Refactor too-many-nested-statements where possible
    * Suppress type checked errors where member is dynamically added (notably derived from josepy.JSONObjectWithFields)
    * Remove None default of func parameter for ExitHandler and ErrorHandler

Resolves #5973

certbot-dns-dnsmadeeasy/certbot_dns_dnsmadeeasy/dns_dnsmadeeasy.py

@@ -79,7 +79,7 @@ class _DNSMadeEasyLexiconClient(dns_common_lexicon.LexiconClient):
 
     def _handle_http_error(self, e, domain_name):
         if domain_name in str(e) and str(e).startswith('404 Client Error: Not Found for url:'):
-            return
+            return None
 
         hint = None
         if str(e).startswith('403 Client Error: Forbidden for url:'):