Creating a new user

As an admin, I want to be able to create a new user so that we could have more customers in our bank.

Acceptance criteria

Fairly simple POST endpoint /api/v1/users that takes a requestbody of a new User class.

A new user is generated from this requestbody and a new user is added to the database.

It is important to use BCryptPasswordEncoder() to encrypt the password, otherwise Spring Boot is not happy.