Get behavior of gitlab_project_members to the one of gitlab_group_members (#3319) (#3383)

* Initial change to get behaviour of gitlab_project_members like the new gitlab_group_members

* added changelog

* linter: removed trainling whitespaces

* Update plugins/modules/source_control/gitlab/gitlab_project_members.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/source_control/gitlab/gitlab_project_members.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/source_control/gitlab/gitlab_project_members.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/source_control/gitlab/gitlab_project_members.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/source_control/gitlab/gitlab_project_members.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* requested changes

* linter fixes

* undoing formatting changes to existing code

Co-authored-by: Max-Florian Bidlingmaier <Max.Bidlingmaier@konsolan.de>
Co-authored-by: Felix Fontein <felix@fontein.de>
Co-authored-by: Max Bidlingmaier <Max-Florian.Bidlingmaier@sap.com>
(cherry picked from commit 7a2efb4775)

Co-authored-by: Max Bidlingmaier <maks@konsolan.de>

tests/integration/targets/gitlab_project_members/defaults/main.yml

@@ -3,3 +3,11 @@ gitlab_api_access_token: "token"
 gitlab_project: some_project
 username: some_user
 gitlab_access_level: developer
+userlist:
+  - username1
+  - username2
+dedicated_access_users:
+  - name: username1
+    access_level: "developer"
+  - name: username2
+    access_level: "maintainer"