As mentioned in https://github.com/certbot/certbot/pull/7712#discussion_r370419867, it's time to remove this ciphersuite now that Windows 2008 R2 and Windows 7 are EOLed.
* Remove ECDHE-RSA-AES128-SHA from NGINX ciphers list to celebrate Windows 2008 R2 deprecation
* Update changelog
Part of #5775.
* Create _internal folder certbot-nginx
* Move configurator.py to _internal
* Move constants.py to _internal
* Move display_ops.py to _internal
* Move http_01.py to _internal
* Move nginxparser.py to _internal
* Move obj.py to _internal
* Move parser_obj.py to _internal
* Move parser.py to _internal
* Update location and references for tls_configs
* exclude parser_obj from coverage