Use micronaut security

[Vorlent]

Cozycast needs a security layer to allow admins to login and perform certain maintenance tasks. Later it may become necessary to implement an optional registration system that lets people verify their account and save user specific data in the database instead of the client.

This means there will be an endpoint that lets users enter their username and password to obtain a token which is then stored in localstorage.

Finally I will need a custom AuthenticationProvider to associate roles with usernames in the database.

[Vorlent]

Micronaut security has been integrated into cozycast.