feat(alertmanager_receiver): add role

roles/alertmanager_receiver/meta/main.yml

@@ -0,0 +1,14 @@
+---
+allow_duplicates: true
+dependencies: []
+galaxy_info:
+  role_name: alertmanager_receiver
+  description: >-2
+    `matrix-alertmanager-receiver` is a receiver for alerts generated by alertmanager.
+    This role supports both `docker` and `podman` based deployments.
+  galaxy_tags:
+    - matrix
+    - alertmanager
+    - metio
+    - docker
+    - podman