add bootstrapping tools

[rethab]

in particular the user list is quite cumbersome to create. would be good if there was a way to (semi) automatically create that list by fetching all users from jira and slack.

[rethab]

Listing jira users implemented with c1495b8 however listing slack user is not so easy due to missing functionality in the upstream slack library (although slack would support it): https://github.com/flyberry-capital/scala-slack