feat: add blackbox monitoring and app3 deployment

- Add blackbox exporter role and playbooks
- Add cadvisor, docker, httpbin roles
- Add app3 deployment playbooks
- Configure blackbox monitoring

playbooks/deploy-app3-cadvisor.yml

@@ -0,0 +1,16 @@
+---
+- name: Deploy cAdvisor on App3
+  hosts: 192.168.0.112
+  become: yes
+  gather_facts: yes
+
+  pre_tasks:
+    - name: Ensure Docker is installed
+      include_role:
+        name: docker
+        apply:
+          tags: docker
+
+  roles:
+    - role: cadvisor
+      tags: cadvisor