Improved the scenario risk QA tests
Removed the ScenarioGetter special case
Removed the fake dependency on task_no from the hazard_getters
Added a forgotten migration
Simplified the GMF getters
Merged from master
Merge branch 'master' into fix-ordering-hazard-getters
Fixed the numbers in scenario/case_2
Now risk calculations require the hazard_job_id, not the hazard_calculation_id
Added the option --hazard-job-id
Now the ProbabilisticEventBased demo uses the new feature
Removed the obsolete option --hazard-calculation-id
Added a docstring
Merge pull request #1506 from gem/fix-ordering-hazard-getters

Replaced the ScenarioGetter with the GroundMotionFieldGetter
Changed the output_weight for the event based calculator
Increased readability
Merge pull request #1508 from gem/hazard_job

Introduced --hazard-job-id and made it possible to reuse exposures imported in the hazard part of the computation
Better explanation of the weight normalization factor
Merge pull request #1511 from gem/output-weight

Changed the output_weight for the event based calculator
Fixed a test broken by the change in the output_weight