User directory improvements
As a system administrator I need to create users that are not manageable
Just like the in-memory users, the Jpa user directory needs a column representing a "manageable" flag that, when set to true, will lead to the "manageable" attribute on the user being passed to the admin UI so that demo guests won't be able to alter the roles of system users or automatically generated users.
As an user I need to know how many users are registered
To be able to filter and page users in the admin UI a countUser mehtod is required in the user directory service
Added creation of a per-tenant administrative user and group
As part of this commit, special treatment for users created by the InMemoryUserProvider had to be adjusted and moved to more generic places.