slapos-proxy: install slapos-node with package role on debian

CentOS has exception, so we keep installing with tasks

playbook/roles/slapos-proxy/meta/main.yml

 ---
 dependencies:
   - { role: repository, when: not slapos_ansible_offline}
+  - { role: package, package_name: slapos-node, package_state: present, when: ansible_distribution != "CentOS"}

playbook/roles/slapos-proxy/tasks/main.yml

@@ -10,10 +10,6 @@
       state: directory
       mode: 0755
 
-  - name: Install slapos-node on Debian
-    apt: name=slapos-node state=present update_cache=yes cache_valid_time=3600
-    when: ansible_os_family == "Debian" and not slapos_ansible_offline
-
   - name: Uninstall firewalld on CentOS
     yum: name=firewalld state=absent update_cache=yes
     when: ansible_distribution == "CentOS"