Fix all 300+ ansible-lint-reported errors

roles/custom/matrix-dendrite/tasks/setup_install.yml

@@ -42,24 +42,20 @@
   delay: "{{ devture_playbook_help_container_retries_delay }}"
   until: result is not failed
 
-- name: Check if a Dendrite signing key exists
-  ansible.builtin.stat:
-    path: "{{ matrix_dendrite_config_dir_path }}/{{ matrix_server_fqn_matrix }}.signing.pem"
-  register: matrix_dendrite_signing_key_stat
-
 # We do this so that the signing key would get generated.
 # We don't use the `docker_container` module, because using it with `cap_drop` requires
 # a very recent version, which is not available for a lot of people yet.
 - name: Generate Dendrite signing key
-  ansible.builtin.command: |
-    docker run
-    --rm
-    --name=matrix-dendrite-config
-    --entrypoint=generate-keys
-    --mount type=bind,src={{ matrix_dendrite_config_dir_path }},dst=/data
-    {{ matrix_dendrite_docker_image }} --private-key=/data/{{ matrix_server_fqn_matrix }}.signing.pem
-    generate
-  when: "not matrix_dendrite_signing_key_stat.stat.exists"
+  ansible.builtin.command:
+    cmd: |
+      docker run
+      --rm
+      --name=matrix-dendrite-config
+      --entrypoint=generate-keys
+      --mount type=bind,src={{ matrix_dendrite_config_dir_path }},dst=/data
+      {{ matrix_dendrite_docker_image }} --private-key=/data/{{ matrix_server_fqn_matrix }}.signing.pem
+      generate
+    creates: "{{ matrix_dendrite_config_dir_path }}/{{ matrix_server_fqn_matrix }}.signing.pem"
 
 - name: Ensure Dendrite server key exists
   ansible.builtin.file: