Implement HTTP-01 challenge for Nginx (#5414)

* get http01 challenge working

* support multiple challenge types in configurator.py

* update existing nginx tests

* lint

* refactor NginxHttp01 and NginxTlsSni01 to both now  inherit from NginxChallengePerformer

* remove TODO

* challenges_test tests with both tlssni01 and http01

* Make challenges.py more abstract to make lint happier

* add pylint disables to the tests to make pylint happier about the inheritance and abstraction situation

* no need to cover raise NotImplementedError() lines

* python3 compatibility

* test that http01 perform is called

* only remove ssl from addresses during http01

* Initialize addrs_to_add

* Change Nginx http01 to modify server block so the site doesn't stop serving while getting a cert

* pass existing unit tests

* rename sni --> http01 in unit tests

* lint

* fix configurator test

* select an http block instead of https

* properly test for port number

* use domains that have matching addresses

* remove debugger

* remove access_log and error_log cruft that wasn't being executed

* continue to return None from choose_redirect_vhost when create_if_no_match is False

* add nginx integration test

certbot-nginx/tests/boulder-integration.conf.sh

@@ -49,10 +49,10 @@ http {
 
   server {
     # IPv4.
-    listen 8081;
+    listen 5002;
     # IPv6.
-    listen [::]:8081 default ipv6only=on;
-    server_name nginx.wtf;
+    listen [::]:5002 default ipv6only=on;
+    server_name nginx.wtf nginx2.wtf;
 
     root $root/webroot;