Modularize setting GNOME config into its own role

I see it will be useful for setting to other Linux-based operating
systems.

playbooks/fedora-workstation.yml

@@ -79,18 +79,3 @@
           - ansible-doc
           - ansible-collection-community-general
           - python3-psutil
-
-    # Configure desktop environment.
-    - name: Install dconf keyfiles
-      copy:
-        src: ./files/dconf/
-        dest: /etc/dconf/db/a-happy-gnome.d
-
-    - name: Set 'user' dconf profile with the custom GNOME config
-      ansible.builtin.shell: echo "system-db:a-happy-gnome" >> /etc/dconf/profile/user
-
-    - name: Enable night light in GNOME
-      dconf:
-        state: present
-        key: /org/gnome/settings-daemon/plugins/color/night-light-enabled
-        value: "true"

roles/system/gnome/tasks/main.yml

@@ -0,0 +1,17 @@
+---
+- name: Install dconf keyfiles
+  copy:
+    src: "{{ role_path }}/files/dconf/"
+    dest: /etc/dconf/db/a-happy-gnome.d
+
+- name: Set 'user' dconf profile with the custom GNOME config
+  ansible.builtin.shell: grep "system-db:a-happy-gnome" && echo "system-db:a-happy-gnome" >> /etc/dconf/profile/user
+
+- name: Update dconf database
+  ansible.builtin.shell: dconf update
+
+- name: Enable night light in GNOME
+  dconf:
+    state: present
+    key: /org/gnome/settings-daemon/plugins/color/night-light-enabled
+    value: "true"