feat: keycloak integration and s3 as a backend storage

[ymarcon]

In ENAC IT's keycloak:

• added realm EERL federating the EPFL's LDAP
• added icebreaker-admin role
• added some users to this role
• added clients: one for the ui (frontend) and one for the api (backend)

In frontend:

• use of keycloak-js to openid connect to keycloak in EERL's realm
• get roles from authenticated user
• display gui features according to the admin role
• send an access token to backend's endpoints requiring specific authorization

In backend:

• some endpoints require proper authz
• validate provided access token against keycloak
• get user roles
• authorize feature exec according to role

[pierreleripoll]

Love the usage of S3 for storing campaings Also keycloack works super nice