Make all doc fragments, module utils, and plugin utils private (#11896)

* Make all doc fragments private.

* Make all plugin utils private.

* Make all module utils private.

* Reformat.

* Changelog fragment.

* Update configs and ignores.

* Adjust unit test names.

plugins/doc_fragments/_gitlab.py

@@ -0,0 +1,37 @@
+# Copyright (c) Ansible project
+# 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 doc fragment 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 annotations
+
+
+class ModuleDocFragment:
+    # Standard files documentation fragment
+    DOCUMENTATION = r"""
+requirements:
+  - requests (Python library U(https://pypi.org/project/requests/))
+
+options:
+  api_token:
+    description:
+      - GitLab access token with API permissions.
+    type: str
+  api_oauth_token:
+    description:
+      - GitLab OAuth token for logging in.
+    type: str
+    version_added: 4.2.0
+  api_job_token:
+    description:
+      - GitLab CI job token for logging in.
+    type: str
+    version_added: 4.2.0
+  ca_path:
+    description:
+      - The CA certificates bundle to use to verify GitLab server certificate.
+    type: str
+    version_added: 8.1.0
+"""