Enable authentication and authorization in the test environment

For the moment, the test environment does not use TLS, which makes it unable to use authentication or authorization. Thus, both features are not tested for the moment.

The TLS support should be enabled in Ansible, with certificates being automatically created. This would allow the use of RBAC authorization as well.

Actual changes (maybe not exhaustive)

• TLS support (authentication) (addressed by #250 (closed)):
  • install cfssl using apt;
  • generation of certificates for each Krake component using cfssl and support/pki;
  • enable TLS in the configuration;
  • set the certificate path in the configuration of the Krake components (including rok).
• RBAC (authorization):
  • set RBAC as authorization mode in the configuration;
  • use the bootstrapping script to add the base roles in the database.