Impact Function Centric Wizard 

This PR contains:

- the wizard itself
- safe.utilities.analysis_handler.AnalysisHandler class for managing signals from Analysis and generating reports. The dock will probably reuse it in the future as agreed with Ismail.
- an additional signal in ExtentSelectorDialog to call it from the wizard
- changes to ImpactFunctionManager and ImpactFunctionMetadata, that were present in Ismail's branches the wizard is based on, but seems they are not merged to develop yet.
- a small fix to safe.test.utilities.clone_raster_layer