[Windows] Security model for files permissions - STEP 1 (#6893)

This PR is the first part of #6497 to ease the integration, following the new plan propose by @bmw here: #6497 (comment)

This step 1 refactor existing certbot.compat module into certbot.compat.misc, without any logic changed. Package certbot.compat will host the new modules that constitute the security model for Windows.

* Create the certbot.compat package. Move logic in certbot.compat.misc

* Add doc

* Fix lint

* Correct mypy

* Update client.py

certbot/display/util.py

@@ -6,10 +6,10 @@ import textwrap
 
 import zope.interface
 
-from certbot import compat
 from certbot import constants
-from certbot import interfaces
 from certbot import errors
+from certbot import interfaces
+from certbot.compat import misc
 from certbot.display import completer
 
 logger = logging.getLogger(__name__)
@@ -79,7 +79,7 @@ def input_with_timeout(prompt=None, timeout=36000.0):
         sys.stdout.write(prompt)
         sys.stdout.flush()
 
-    line = compat.readline_with_timeout(timeout, prompt)
+    line = misc.readline_with_timeout(timeout, prompt)
 
     if not line:
         raise EOFError