docker_container: allow arbitrary log_driver (#33579)

Docker supports logging plugin (see https://docs.docker.com/engine/admin/logging/plugins)
so it no longer makes sense to limit the log_driver option to a set of
fixed choices.

lib/ansible/modules/cloud/docker/docker_container.py

@@ -182,16 +182,9 @@ options:
       - Setting this will force container to be restarted.
   log_driver:
     description:
-      - Specify the logging driver. Docker uses json-file by default.
-    choices:
-      - none
-      - json-file
-      - syslog
-      - journald
-      - gelf
-      - fluentd
-      - awslogs
-      - splunk
+      - Specify the logging driver. Docker uses I(json-file) by default.
+      - See L(here,https://docs.docker.com/config/containers/logging/configure/) for possible choices.
+    required: false
   log_options:
     description:
       - Dictionary of options specific to the chosen log_driver. See https://docs.docker.com/engine/admin/logging/overview/
@@ -2102,9 +2095,7 @@ def main():
         kill_signal=dict(type='str'),
         labels=dict(type='dict'),
         links=dict(type='list'),
-        log_driver=dict(type='str',
-                        choices=['none', 'json-file', 'syslog', 'journald', 'gelf', 'fluentd', 'awslogs', 'splunk'],
-                        default=None),
+        log_driver=dict(type='str'),
         log_options=dict(type='dict', aliases=['log_opt']),
         mac_address=dict(type='str'),
         memory=dict(type='str', default='0'),