Buildbot documentation for individual developers

Kaj to interview Vlad and write first GDoc for Rasmus review

• Description of the naming of branches and how that impacts what Buildbot does
  • What should I do to get Buildbot to build my branch?
  • Git command example of what to do to get my code in my branch to be tested by buildbot
• Does Buildbot build pull requests and if it does how?
• MariaDB Server does not have protected branches in use currently in Github, but if it would it would be necessary to explain what status checks are enabled and what it means from a buildbot perspective.
• List of platforms not covered by Buildbot
• Since staging branch(es) are being introduced the whole sequence from developing code, pushing to own branch, getting it to staging, what happens then sequence should be explained