Move roles/matrix* to roles/custom/matrix*

This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

roles/custom/matrix-synapse/tasks/ext/synapse-simple-antispam/setup.yml

@@ -0,0 +1,7 @@
+---
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/ext/synapse-simple-antispam/setup_install.yml"
+  when: matrix_synapse_ext_spam_checker_synapse_simple_antispam_enabled | bool
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/ext/synapse-simple-antispam/setup_uninstall.yml"
+  when: "not matrix_synapse_ext_spam_checker_synapse_simple_antispam_enabled | bool"

roles/custom/matrix-synapse/tasks/ext/synapse-simple-antispam/setup_install.yml

@@ -0,0 +1,58 @@
+---
+
+- name: Fail if Synapse Simple Antispam blocked homeservers is not set
+  ansible.builtin.fail:
+    msg: "Synapse Simple Antispam is enabled, but no blocked homeservers have been set in matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeservers"
+  when: "matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeservers | length == 0"
+
+- name: Ensure git installed (RedHat)
+  ansible.builtin.yum:
+    name:
+      - git
+    state: present
+    update_cache: false
+  when: "ansible_os_family == 'RedHat'"
+
+- name: Ensure git installed (Debian)
+  ansible.builtin.apt:
+    name:
+      - git
+    state: present
+    update_cache: false
+  when: "ansible_os_family == 'Debian'"
+
+- name: Ensure git installed (Archlinux)
+  community.general.pacman:
+    name:
+      - git
+    state: present
+    update_cache: false
+  when: "ansible_distribution == 'Archlinux'"
+
+- name: Clone synapse-simple-antispam git repository
+  ansible.builtin.git:
+    repo: "{{ matrix_synapse_ext_spam_checker_synapse_simple_antispam_git_repository_url }}"
+    version: "{{ matrix_synapse_ext_spam_checker_synapse_simple_antispam_git_version }}"
+    dest: "{{ matrix_synapse_ext_path }}/synapse-simple-antispam"
+  become: true
+  become_user: "{{ matrix_user_username }}"
+
+- ansible.builtin.set_fact:
+    matrix_synapse_modules: >
+      {{
+        matrix_synapse_modules
+        +
+        [{
+          "module": "synapse_simple_antispam.AntiSpamInvites",
+          "config": {
+            "blocked_homeservers": matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeservers
+          }
+        }]
+      }}
+
+    matrix_synapse_container_extra_arguments: >
+      {{
+        matrix_synapse_container_extra_arguments | default([])
+        +
+        ["--mount type=bind,src={{ matrix_synapse_ext_path }}/synapse-simple-antispam/synapse_simple_antispam,dst={{ matrix_synapse_in_container_python_packages_path }}/synapse_simple_antispam,ro"]
+      }}

roles/custom/matrix-synapse/tasks/ext/synapse-simple-antispam/setup_uninstall.yml

@@ -0,0 +1,6 @@
+---
+
+- name: Ensure synapse-simple-antispam doesn't exist
+  ansible.builtin.file:
+    path: "{{ matrix_synapse_ext_path }}/synapse-simple-antispam"
+    state: absent