fix up acme & certbot standalone code (#10293)

certbot's standalone code contains confusing references to things like
`SSLSocket` which we were hoping to deprecate in
https://github.com/certbot/certbot/issues/10284. are they relevant?
they're sure not!

certbot's standalone plugin only supports HTTP-01 so comments about
things like `ACMETLSServer` and the completely unused `certs` variable
can be deleted

furthermore, the type of the different variables named things like
`http_01_resources` were wrong in multiple places. as can be seen in
certbot's standalone code, the type is
`Set[acme_standalone.HTTP01RequestHandler.HTTP01Resource]`. this is also
[the type used in acme.standalone's
tests](https://github.com/certbot/certbot/blob/723fe64d4dbc778f1e8fd0b93320c1a30dc6fa95/acme/src/acme/_internal/tests/standalone_test.py#L78-L81)
despite the file's type annotations saying it takes a different type. i
think the incorrect type annotations were never caught because mypy
can't fully make sense of our overly complex server classes here

finally, `from __future__ import annotations` was added to make [forward
references in type
annotations](https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html#forward-references)
easier

acme/src/acme/standalone.py

@@ -1,4 +1,6 @@
 """Support for standalone client challenge solvers. """
+from __future__ import annotations
+
 import collections
 import functools
 import http.client as http_client
@@ -219,7 +221,8 @@ class HTTPServer(BaseHTTPServer.HTTPServer):
 class HTTP01Server(HTTPServer, ACMEServerMixin):
     """HTTP01 Server."""
 
-    def __init__(self, server_address: Tuple[str, int], resources: Set[challenges.HTTP01],
+    def __init__(self, server_address: Tuple[str, int],
+                 resources: Set[HTTP01RequestHandler.HTTP01Resource],
                  ipv6: bool = False, timeout: int = 30) -> None:
         super().__init__(
             server_address, HTTP01RequestHandler.partial_init(
@@ -314,8 +317,8 @@ class HTTP01RequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
                          self.path)
 
     @classmethod
-    def partial_init(cls, simple_http_resources: Set[challenges.HTTP01],
-                     timeout: int) -> 'functools.partial[HTTP01RequestHandler]':
+    def partial_init(cls, simple_http_resources: Set[HTTP01RequestHandler.HTTP01Resource],
+                     timeout: int) -> functools.partial[HTTP01RequestHandler]:
         """Partially initialize this handler.
 
         This is useful because `socketserver.BaseServer` takes

certbot/src/certbot/_internal/plugins/standalone.py

@@ -8,11 +8,9 @@ from typing import DefaultDict
 from typing import Dict
 from typing import Iterable
 from typing import List
-from typing import Mapping
 from typing import Set
 from typing import Tuple
 from typing import Type
-from typing import Union
 from typing import TYPE_CHECKING
 
 from acme import challenges
@@ -23,10 +21,6 @@ from certbot import interfaces
 from certbot.display import util as display_util
 from certbot.plugins import common
 
-from cryptography import x509
-from cryptography.hazmat.primitives.asymmetric import types
-from OpenSSL import crypto
-
 logger = logging.getLogger(__name__)
 
 if TYPE_CHECKING:
@@ -35,30 +29,14 @@ if TYPE_CHECKING:
         Set[achallenges.AnnotatedChallenge]
     ]
 
-_KeyAndCert = Union[
-    Tuple[crypto.PKey, crypto.X509],
-    Tuple[types.CertificateIssuerPrivateKeyTypes, x509.Certificate],
-]
-
 
 class ServerManager:
-    """Standalone servers manager.
+    """Manager for HTTP-01 standalone server instances."""
 
-    Manager for `ACMEServer` and `ACMETLSServer` instances.
-
-    `certs` and `http_01_resources` correspond to
-    `acme.crypto_util.SSLSocket.certs` and
-    `acme.crypto_util.SSLSocket.http_01_resources` respectively. All
-    created servers share the same certificates and resources, so if
-    you're running both TLS and non-TLS instances, HTTP01 handlers
-    will serve the same URLs!
-
-    """
-    def __init__(self, certs: Mapping[bytes, _KeyAndCert],
+    def __init__(self,
                  http_01_resources: Set[acme_standalone.HTTP01RequestHandler.HTTP01Resource]
                  ) -> None:
         self._instances: Dict[int, acme_standalone.HTTP01DualNetworkedServers] = {}
-        self.certs = certs
         self.http_01_resources = http_01_resources
 
     def run(self, port: int, challenge_type: Type[challenges.Challenge],
@@ -144,10 +122,9 @@ running. HTTP challenge only (wildcards not supported)."""
         # values, main thread writes). Due to the nature of CPython's
         # GIL, the operations are safe, c.f.
         # https://docs.python.org/2/faq/library.html#what-kinds-of-global-value-mutation-are-thread-safe
-        self.certs: Mapping[bytes, _KeyAndCert] = {}
         self.http_01_resources: Set[acme_standalone.HTTP01RequestHandler.HTTP01Resource] = set()
 
-        self.servers = ServerManager(self.certs, self.http_01_resources)
+        self.servers = ServerManager(self.http_01_resources)
 
     @classmethod
     def add_parser_arguments(cls, add: Callable[..., None]) -> None:

certbot/src/certbot/_internal/tests/plugins/standalone_test.py

@@ -23,13 +23,11 @@ class ServerManagerTest(unittest.TestCase):
     """Tests for certbot._internal.plugins.standalone.ServerManager."""
 
     def setUp(self):
-        from certbot._internal.plugins.standalone import ServerManager, _KeyAndCert
-        self.certs: Dict[bytes, _KeyAndCert] = {}
+        from certbot._internal.plugins.standalone import ServerManager
         self.http_01_resources: Set[acme_standalone.HTTP01RequestHandler.HTTP01Resource] = {}
-        self.mgr = ServerManager(self.certs, self.http_01_resources)
+        self.mgr = ServerManager(self.http_01_resources)
 
     def test_init(self):
-        assert self.mgr.certs is self.certs
         assert self.mgr.http_01_resources is self.http_01_resources
 
     def _test_run_stop(self, challenge_type):