Update validation for v1.0rc release about gammapy-benchmarks

[registerrier]

Status so far:

• light curve runs and gives consistent results
• joint-crab analyses fails because of rad_max IRF handling:
  • required_irf need to be updated so that psf is taken into account for hess (full containment data)
  • reflected background maker no longer works for pointlike data
• joint-crab-fit runs and yields consistent results

The reflected background issue cannot be easily solved unless we provide a special handling for fixed radmax.
If we are to use wobble regions instead, we need to adapt Analysis to support WobbleRegionFinder.