New Resource gitlab_global_level_notifications to manage global notification on gitlab

New Data Source / Resource

It will be good to be able to config the global level notifications:

resource "gitlab_global_level_notifications" "all_issues" {
    level      = "watch"
}

Or for custom

resource "gitlab_global_level_notifications" "foo" {
    level      = "custom"
    merge_merge_request = true
}

Related GitLab APIs

API documentation:

https://docs.gitlab.com/ee/api/notification_settings.html#global-notification-settings

Additional Details

• GitLab REST API resources available (read for data sources, crud for resources)
• go-gitlab does support the related GitLab API already
• I'd like to contribute it myself