Add report functionality to ui-flex and flex

[Fohlen]

This could be done by

• using https://pastee.github.io/docs/#pastes
• step by step
  • add a report button to the ui-flex
  • add a /api/v1/flex/report function
  • this function uses sysinfo, version and log (you need to iterate over all log names)
  • pastes to e.g pastee
  • once pasting is complete, return the link to the user

Just for the protocol, this is a sub-issue of #521