4506: Export settings through the UI


What version are you running?


What's the URL of the page this enhancement relates to, if any?


Describe the enhancement and the motivation for it.

Provide a UI to export/import settings (such as users, repos, default reviewers especially...) from one instance to another instance of RB.
I added a hundred or so default reviewer rules to a test instance of RB in a Docker, i now want to put this configuration into production outside of the docker.
Having a UI to export such settings would save us the hassle of manipulating the MySQL database, ending with bad UTF-8 encoding alerts.

What operating system are you using? What browser?

Linux Ubuntu 16.04 LTS / Firefox 50

Please provide any additional information below.