* SysRoot can always be determined from kit.
* Pass around RunMode as extra parameter
  not as part of AnalyzerStartParameters.
  That's closer to the pattern used elsewhere.
* Environment was always initialized from the runconfig's
  EnvironmentAspect. The tools can do that directly.
* Provide setter for display name for cases where
  it is not equal to RunConfiguration::displayName

Change-Id: I811a0d7cdeb55cc37a16a593b3942abb567a2150
Reviewed-by: BogDan Vatra <bogdan@kdab.com>
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>