Added UserRepository.java class,
allowing to mimic some User in-memory DAO
Provided implementation for basicPrincipalAuthenticator() in AppModule
Relying on UserRepository injected component
Added dep on restx-admin (thus on restx-security-basic)
Provided spec tests trying to call hello route
with different users (and roles)

Had a hard part to be able to sign cookie whereas signature key was randomly generated :
I had to provide a Mustache template block in order to succeed