alloy(role): add documentation

- add README
- add argument_specs
- removed tags

roles/alloy/tasks/install.yaml

@@ -0,0 +1,20 @@
+---
+- name: Add grafana apt repo with signing key
+  become: true
+  ansible.builtin.deb822_repository:
+    name: grafana
+    types: deb
+    uris: https://apt.grafana.com
+    suites: "{{ ansible_facts['distribution_release'] }}"
+    components:
+      - main
+    signed_by: https://apt.grafana.com/gpg.key
+
+- name: Run cache update
+  ansible.builtin.apt:
+    update_cache: true
+
+- name: Install alloy
+  become: true
+  ansible.builtin.package:
+    name: alloy