Add additional auth support to Gitlab (#705) (#3918)

* Add additional auth support to Gitlab (#705)

- removed unused imports from module_utils.gitlab
- fix bug in gitlab_project to check if avatar_path is provided

* add doc_fragment and argument_spec for gitlab auth

* doc fixes and remove avatar_path bug fix

* small doc changes, pass validate_certs to requests call

* update changelog

plugins/doc_fragments/gitlab.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+
+class ModuleDocFragment(object):
+
+    # 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
+'''