Add support for using custom ACME CA servers (other than Let's Encrypt')

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1468

roles/matrix-nginx-proxy/defaults/main.yml

@@ -442,7 +442,14 @@ matrix_ssl_domains_to_obtain_certificates_for: "{{ matrix_ssl_additional_domains
 matrix_ssl_additional_domains_to_obtain_certificates_for: []
 
 # Controls whether to obtain production or staging certificates from Let's Encrypt.
+# If you'd like to use another ACME certificate server (not Let's Encrypt), see `matrix_ssl_lets_encrypt_server`
 matrix_ssl_lets_encrypt_staging: false
+
+# Controls the server used to retrieve the SSL certificates (passed as a `--server` flag to Certbot).
+# By default, we use the Let's Encrypt production environment (see `matrix_ssl_lets_encrypt_staging` for using the staging environment).
+# Learn more here: https://eff-certbot.readthedocs.io/en/stable/using.html#changing-the-acme-server
+matrix_ssl_lets_encrypt_server: ''
+
 matrix_ssl_lets_encrypt_certbot_docker_image: "{{ matrix_container_global_registry_prefix }}certbot/certbot:{{ matrix_ssl_architecture }}-v1.21.0"
 matrix_ssl_lets_encrypt_certbot_docker_image_force_pull: "{{ matrix_ssl_lets_encrypt_certbot_docker_image.endswith(':latest') }}"
 matrix_ssl_lets_encrypt_certbot_standalone_http_port: 2402

roles/matrix-nginx-proxy/tasks/ssl/setup_ssl_lets_encrypt_obtain_for_domain.yml

@@ -42,6 +42,7 @@
     --non-interactive
     --work-dir=/tmp
     --http-01-port 8080
+    {% if matrix_ssl_lets_encrypt_server %}--server={{ matrix_ssl_lets_encrypt_server|quote }}{% endif %}
     {% if matrix_ssl_lets_encrypt_staging %}--staging{% endif %}
     --standalone
     --preferred-challenges http
@@ -70,6 +71,7 @@
     --non-interactive
     --work-dir=/tmp
     --http-01-port 8080
+    {% if matrix_ssl_lets_encrypt_server %}--server={{ matrix_ssl_lets_encrypt_server|quote }}{% endif %}
     {% if matrix_ssl_lets_encrypt_staging %}--staging{% endif %}
     --standalone
     --preferred-challenges http