* Available choices: "http_https" and "websocket"

* Add mapping property "sorry_page". Must be an URL, default value is
  configurable (see next point)
* Add new plugin configuration "default_sorry_page" default to https://sorry.ec.europa.eu/
* Fixed mapping import form don't expose all mapping properties

* Properties are:
  - gzip_proxied
  - keepalive_timeout
  - proxy_cache
  - proxy_read_timeout
  - client_max_body_size
* Add E2E tests

Mapping can now have SAML Coniguration:

* Only API was implemented

* Add start and halt testing environment Ansible playbook
* Add test CI stage
* Change tag for OVH