[Futurev4] Add a test for running Gauss with DD4hep geometry and fix problems

needs !742 (merged)

Add a test for running Gauss with DD4hep geometry

The test is based on the example at https://gitlab.cern.ch/Gaussino/futuregaussexamples/-/blob/854f8978601a669342101901aa74927a2730c6fb/dd4hep/main.md

The test is placed in a temporary new package (Sim/FutureTests) since the tests in Sim/Gauss are disabled.

Fix configuration for output file writing

Until this change, the writer GaussTape was run too early by the AvalancheScheduler because its dependencies are not declared.

Here the GaussTape writer and the packers are now wrapped into GaudiSequencer-s which tells the AvalancheScheduler that GaussTape must run after the packing. Similarly, MCTruthToEDM is explicitly scheduled before the packers (which also don't delcare their inputs). With these changes, one can write out a .sim file as long as a single thread is used.

Fix list of XML includes for VP (follow Detector!76 (merged))

Fix copy-paste bug with EvtGenDecay.ImHelOne

EvtGenDecay.ImHelOne was wrongly named RealHelOne causing a collision. As a result the property m_imHelOne had a value of 1 instead of 0.

Add tests for DDG4 simulation scripts

Update 16.06.21 by mimazure This is cherry-picked from 90b0b535 and follows Detector!85 (merged)