Fix issue where RADIUS auth logged to root logger (#637)

I was looking for this, because I made the same kind of mistake in
another library.

TBH, I think SonarCloud should create a rule to find these cases.
`logging.info` goes to the _root_ logger. That is almost never what you
want. Any configuration of the `ansible_base` logger will be ignored. I
don't think we even customize the root logger in most cases, so the
messages would likely be lost.

The python standard library is deceptively permissive of this. Even
though these cases are almost certainly a typo/goof, python accepts it
as the programmer's intention.

ansible_base/authentication/authenticator_plugins/_radiusauth.py

@@ -39,6 +39,9 @@
 #Handle custom user models
 from django.contrib.auth import get_user_model
 from django.contrib.auth.models import Group
+
+logger = logging.getLogger('ansible_base.authentication.authenticator_plugins._radiusauth')
+
 User = get_user_model()
 
 DICTIONARY = u"""
@@ -149,23 +152,23 @@ def _perform_radius_auth(self, client, packet):
         try:
             reply = client.SendPacket(packet)
         except Timeout as e:
-            logging.error("RADIUS timeout occurred contacting %s:%s" % (
+            logger.error("RADIUS timeout occurred contacting %s:%s" % (
                 client.server, client.authport))
             return None
         except Exception as e:
-            logging.error("RADIUS error: %s" % e)
+            logger.error("RADIUS error: %s" % e)
             return None
 
         if reply.code == AccessReject:
-            logging.warning("RADIUS access rejected for user '%s'" % (
+            logger.warning("RADIUS access rejected for user '%s'" % (
                 packet['User-Name']))
             return None
         elif reply.code != AccessAccept:
-            logging.error("RADIUS access error for user '%s' (code %s)" % (
+            logger.error("RADIUS access error for user '%s' (code %s)" % (
                 packet['User-Name'], reply.code))
             return None
 
-        logging.info("RADIUS access granted for user '%s'" % (
+        logger.info("RADIUS access granted for user '%s'" % (
             packet['User-Name']))
 
         if "Class" not in reply.keys():
@@ -190,7 +193,7 @@ def _perform_radius_auth(self, client, packet):
                 elif role == "superuser":
                     is_superuser = True
                 else:
-                    logging.warning("RADIUS Attribute Class contains unknown role '%s'. Only roles 'staff' and 'superuser' are allowed" % cl)
+                    logger.warning("RADIUS Attribute Class contains unknown role '%s'. Only roles 'staff' and 'superuser' are allowed" % cl)
         return groups, is_staff, is_superuser
 
     def _radius_auth(self, server, username, password):
@@ -232,7 +235,7 @@ def get_user_groups(self, group_names):
         groups = Group.objects.filter(name__in=group_names)
         if len(groups) != len(group_names):
             local_group_names = [g.name for g in groups]
-            logging.warning("RADIUS reply contains %d user groups (%s), but only %d (%s) found" % (
+            logger.warning("RADIUS reply contains %d user groups (%s), but only %d (%s) found" % (
                 len(group_names), ", ".join(group_names), len(groups), ", ".join(local_group_names)))
         return groups