What version are you running?
2.5.7
What's the URL of the page this enhancement relates to, if any?
/admin
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.