Move self-building git repository URLs to variables (stop hardcoding)

roles/matrix-synapse/defaults/main.yml

@@ -4,6 +4,7 @@
 matrix_synapse_enabled: true
 
 matrix_synapse_container_image_self_build: false
+matrix_synapse_container_image_self_build_repo: "https://github.com/matrix-org/synapse.git"
 
 matrix_synapse_docker_image: "{{ matrix_synapse_docker_image_name_prefix }}matrixdotorg/synapse:v1.23.0"
 matrix_synapse_docker_image_name_prefix: "{{ 'localhost/' if matrix_synapse_container_image_self_build else 'docker.io/' }}"

roles/matrix-synapse/tasks/synapse/setup_install.yml

@@ -20,7 +20,7 @@
 
 - name: Ensure Synapse repository is present on self-build
   git:
-    repo: https://github.com/matrix-org/synapse.git
+    repo: "{{ matrix_synapse_container_image_self_build_repo }}"
     dest: "{{ matrix_synapse_docker_src_files_path }}"
     version: "{{ matrix_synapse_docker_image.split(':')[1] }}"
     force: "yes"