CI: molecule fixes

- use become: true when running bootstrap-os in molecule
- match host name in bastion-ssh-config to not confuse the provisionner

roles/bootstrap-os/molecule/default/converge.yml

@@ -2,5 +2,6 @@
 - name: Converge
   hosts: all
   gather_facts: false
+  become: true
   roles:
     - role: bootstrap-os