[HAPI JSON] Support connecting RabbitMQ with TLS

This pull request adds TLS support HAPI JSON.

This pull request adds the following columns to `arm_plugins`:

  * `tls_certificate_path`:
    * The path of TLS certificate for the client (= Hatohol itself).
  * `tls_key_path`:
    * The path of private key for the tls_certificate.
  * `tls_ca_certificate_path`:
    * The path of TLS certificate of CA.

We need to set these columns to connect RabbitMQ with TLS.

There is no UI to set these TLS configurations. We need to set them by SQL directly like:

    UPDATE arm_plugins
      SET tls_key_path = '/etc/hatohol/tls/client/key.pem',
              tls_certificate_path = '/etc/hatohol/tls/client/cert.pem',
              tls_ca_certificate_path = '/etc/hatohol/tls/CA/cacert.pem'
      WHERE id = 1;