Create sub-users for each entity

[overeha]

Currently the resource allows for creating NGO admins, DSU admins etc. Each of the users represents a type of organisation.

The admin users should be able to add new users from ther organisation. Example: if MKBT organisation has an NGO admin account managed by the legal representative, this user should be able to add new staff users to his organisation to help him manage his resources. The staff user should be allowed to manage resources, but cannot delete the account or manage the organisation's profile