ui: Make user table available for every user

[mathiashoeld]

Current situation

The user needs to have one of the following permissions to see the table of users and groups:

• global.createUser
• global.createGroup
• global.listPermissions

Proposed change

Since the change password feature has been added (#325), the user should be able to update his/her password anytime. Therefore the table should be available to all users. The actions like changing the permissions or creating new users is checked on the table itself again, so no actions can be performed without the proper permission.