r/vmagent: Deploy vmagent

The *vmagent* role installs and configures the scraping and routing
agent used in the Victoria Metrics ecosystem.

roles/vmagent/tasks/install.yml

@@ -0,0 +1,11 @@
+- name: ensure vmagent systemd unit is installed
+  copy:
+    src: vmagent.service
+    dest: /etc/systemd/system/vmagent.service
+    mode: '0644'
+  notify:
+  - reload systemd
+  - restart vmagent
+  tags:
+  - service
+  - systemd