Introduce a timeout for package installation

Sometimes package installations can get into weird state and stuck for a
very long time.
Timeout the tasks to fail early, with a customizable timeout duration.

roles/system_packages/defaults/main.yml

@@ -1,4 +1,5 @@
 ---
 # number of times package install task should be retried
 pkg_install_retries: 4
+pkg_install_timeout: "{{ 5 * 60 }}"
 yum_repo_dir: /etc/yum.repos.d