Adapt to ROOT 6.22 python library ROOTTPython

[andresailer]

Fixes another part of #625

BEGINRELEASENOTES

• CMake: Adapt to ROOT 6.22 python library ROOTTPython

ENDRELEASENOTES

This PR is at the moment for testing against dev3.
While this PR here include s #631, #631 should just be merged by itself.

[andresailer]

The installation is now working, but ddsim fails:

---running test :  ' ddsim --compactFile=/DD4hep/DDDetectors/compact/SiD.xml --runType=batch -G -N=2 --outputFile=testSid.root --gun.position "0.0 0.0 1.0*cm" --gun.direction "1.0 0.0 1.0" --gun.energy 100*GeV --part.userParticleHandler= '
Traceback (most recent call last):
  File "/DD4hep/bin/ddsim", line 24, in <module>
    RUNNER.run()
  File "/DD4hep/lib/python2.7/site-packages/DDSim/DD4hepSimulation.py", line 294, in run
    import DDG4
  File "/cvmfs/sft-nightlies.cern.ch/lcg/nightlies/dev3/Wed/ROOT/HEAD/x86_64-centos7-gcc9-opt/lib/python2.7/site-packages/ROOT/_facade.py", line 102, in _importhook
    return _orig_ihook(name, *args, **kwds)
  File "/DD4hep/lib/python2.7/site-packages/DDG4.py", line 13, in <module>
    from dd4hep_base import *  # noqa: F403
  File "/cvmfs/sft-nightlies.cern.ch/lcg/nightlies/dev3/Wed/ROOT/HEAD/x86_64-centos7-gcc9-opt/lib/python2.7/site-packages/ROOT/_facade.py", line 102, in _importhook
    return _orig_ihook(name, *args, **kwds)
  File "/DD4hep/lib/python2.7/site-packages/dd4hep_base.py", line 124, in <module>
    import_namespace_item('core', 'run_interpreter')
  File "/DD4hep/lib/python2.7/site-packages/dd4hep_base.py", line 67, in import_namespace_item
    attr = getattr(scope, nam)
AttributeError: <namespace cppyy.gbl.dd4hep at 0x5d57250> has no attribute 'run_interpreter'. Full details:
  type object 'dd4hep' has no attribute 'run_interpreter'
  'dd4hep::run_interpreter' is not a known C++ class
  'run_interpreter' is not a known C++ template
  'run_interpreter' is not a known C++ enum

*** Error in `python': double free or corruption (!prev): 0x0000000005a96410 ***