Enable all user fields to be updated

[gctucker]

At the moment, only the user name and email can be updated. Once the user management implementation is ready, it should be possible to update all the fields of the profile by the user themselves and other fields by admin users such as is_active.

• API implementation adjusted to allow users to update their own profile
• API implementation adjusted to allow admin users to update all fields including is_active
• Python bindings updated accordingly in kernelci-core
• kci user update and kci user activate / deactivate implemented accordingly
• Unit tests updated accordingly
• End-to-end tests updated accordingly