Add appservice-double-puppet service for better bridge double-puppeting

Bridges will be switched to this new method in future patches.

roles/custom/matrix-appservice-double-puppet/tasks/install.yml

@@ -0,0 +1,23 @@
+---
+
+- name: Ensure matrix-appservice-double-puppet paths exist
+  ansible.builtin.file:
+    path: "{{ item.path }}"
+    state: directory
+    mode: 0750
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  with_items:
+    - path: "{{ matrix_appservice_double_puppet_base_path }}"
+      when: true
+    - path: "{{ matrix_appservice_double_puppet_config_path }}"
+      when: true
+  when: item.when | bool
+
+- name: Ensure matrix-appservice-double-puppet registration configuration installed
+  ansible.builtin.copy:
+    content: "{{ matrix_appservice_double_puppet_registration_configuration | to_nice_yaml(indent=2, width=999999) }}"
+    dest: "{{ matrix_appservice_double_puppet_config_path }}/registration.yaml"
+    mode: 0644
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"

roles/custom/matrix-appservice-double-puppet/tasks/main.yml

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+---
+
+- tags:
+    - setup-all
+    - setup-appservice-double-puppet
+    - install-all
+    - install-appservice-double-puppet
+  block:
+    - when: matrix_appservice_double_puppet_enabled | bool
+      ansible.builtin.include_tasks: "{{ role_path }}/tasks/validate_config.yml"
+
+    - when: matrix_appservice_double_puppet_enabled | bool
+      ansible.builtin.include_tasks: "{{ role_path }}/tasks/install.yml"
+
+- tags:
+    - setup-all
+    - setup-appservice-double-puppet
+  block:
+    - when: not matrix_appservice_double_puppet_enabled | bool
+      ansible.builtin.include_tasks: "{{ role_path }}/tasks/uninstall.yml"

roles/custom/matrix-appservice-double-puppet/tasks/uninstall.yml

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+---
+
+- name: Ensure matrix-appservice-double-puppet paths don't exist
+  ansible.builtin.file:
+    path: "{{ matrix_appservice_double_puppet_base_path }}"
+    state: absent

roles/custom/matrix-appservice-double-puppet/tasks/validate_config.yml

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+---
+- name: Fail if required matrix-appservice-double-puppet settings not defined
+  ansible.builtin.fail:
+    msg: >
+      You need to define a required configuration setting (`{{ item.name }}`).
+  when: "item.when | bool and vars[item.name] == ''"
+  with_items:
+    - {'name': 'matrix_appservice_double_puppet_registration_as_token', when: true}
+    - {'name': 'matrix_appservice_double_puppet_registration_as_token', when: true}
+    - {'name': 'matrix_appservice_double_puppet_registration_sender_localpart', when: true}