Make all doc fragments, module utils, and plugin utils private (#1144)

* Make all doc fragments, module utils, and plugin utils private.

* Remove some unused and no longer needed imports.

This hopefully also fixes the CI issues, which do not happen locally for me...

* Fix formatting.

* Try to make CI happy, again.

* Fix imports.

* Lint.

plugins/plugin_utils/_socket_handler.py

@@ -0,0 +1,25 @@
+# Copyright (c) 2019-2020, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Note that this module util is **PRIVATE** to the collection. It can have breaking changes at any time.
+# Do not use this from other collections or standalone plugins/modules!
+
+from __future__ import absolute_import, division, print_function
+
+
+__metaclass__ = type
+
+
+import selectors
+
+from ansible_collections.community.docker.plugins.module_utils._socket_handler import (
+    DockerSocketHandlerBase,
+)
+
+
+class DockerSocketHandler(DockerSocketHandlerBase):
+    def __init__(self, display, sock, log=None, container=None):
+        super(DockerSocketHandler, self).__init__(
+            sock, selectors, log=lambda msg: display.vvvv(msg, host=container)
+        )