Remove deprecated --dns-route53-propagation-seconds (#10010)

* remove dns-route53-prop-secs

* document design difference

certbot/CHANGELOG.md

@@ -14,6 +14,7 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 * The `csr_dir` and `key_dir` attributes on
   `certbot.configuration.NamespaceConfig` were removed.
 * The `--manual-public-ip-logging-ok` command line flag was removed.
+* The `--dns-route53-propagation-seconds` command line flag was removed.
 
 ### Fixed
 

certbot/certbot/plugins/dns_common.py

@@ -25,6 +25,10 @@ from certbot.plugins import common
 logger = logging.getLogger(__name__)
 
 
+# As of writing this, the only one of our plugins that does not inherit from this class (either
+# directly or indirectly through certbot.plugins.dns_common_lexicon.LexiconDNSAuthenticator) is
+# certbot-dns-route53. If you are attempting to make changes to all of our DNS plugins, please keep
+# this difference in mind.
 class DNSAuthenticator(common.Plugin, interfaces.Authenticator, metaclass=abc.ABCMeta):
     """Base class for DNS Authenticators"""