* add support for get/set/delete user preferences
* make mmctl-docs
* make --category required
---------
Co-authored-by: Mattermost Build <build@mattermost.com>
It was a good decision in hindsight to keep the public module as 0.x
because this would have been a breaking change again.
https://mattermost.atlassian.net/browse/MM-53032
```release-note
Changed the Go module path from github.com/mattermost/mattermost-server/server/v8 to github.com/mattermost/mattermost/server/v8.
For the public facing module, it's path is also changed from github.com/mattermost/mattermost-server/server/public to github.com/mattermost/mattermost/server/public
```
* Includes mmctl into the mono-repo
* Update to use the new public module paths
* Adds docs check to the mmctl CI
* Fix public utils import path
* Tidy up modules
* Fix linter
* Update CI tasks to use the new file structure
* Update CI references
