git_config: support multiple values for same name (#7260)

* Refactor the existing git_config.py

* Support multiple values for same name

tests/integration/targets/git_config/tasks/unset_multi_value.yml

@@ -0,0 +1,28 @@
+---
+# 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
+
+- import_tasks: setup_value.yml
+
+- name: unsetting "push.pushoption"
+  git_config:
+    name: push.pushoption
+    scope: global
+    state: absent
+  register: unset_result
+
+- name: getting all pushoptions values
+  git_config_info:
+    name: push.pushoption
+    scope: global
+  register: get_all_result
+
+- name: assert unsetting muti-values
+  assert:
+    that:
+      - unset_result is changed
+      - 'get_all_result.config_values == {"push.pushoption": []}'
+      - unset_result.diff.before == ["merge_request.create", "merge_request.draft", "merge_request.target=foobar"]
+      - unset_result.diff.after == "\n"
+...