FEATURE REQUEST

1. Is there an open issue addressing this request? If it does, please add a "+1" reaction to the
   existing issue, otherwise proceed to step 2.

There is issue #458.

2. Describe the feature you are requesting, as well as the possible use case(s) for it.
   User removal is a natural feature that we are missing. By initial design, we avoided it due to the complexity of the cascade effect caused by the ownership relation: since only owners could manipulate their Things and Channels, it would imply that removing removes all of its assets in a cascade way. Now, when we introduced administrators and detach access control from ownership, user removal should be as simple as setting a blocked flag or physically removing it. After that, the administrator can take care of all the orphaned assets - remove them or assign them to someone else.
   We also need to introduce refresh tokens and make access tokens last shorter to reduce the possible attack time frame.
   We need to define what removing the user exactly means and do we support user removal or only block it, but either way, it should implement at least one of those two options.

Comments are welcome. @mainflux/maintainers

3. Indicate the importance of this feature to you (must-have, should-have, nice-to-have).
   This is a must-have.