sci-physics/geant: version bumps for Geant4 10.6

sci-physics/geant: version bumps for Geant4 10.6

This set of new ebuilds for Geant4 have been updated to offer more
functionality and be easier to maintain in the future. Here is a
list of the improvements made:

- Moved to EAPI=7
- Same ebuild can be used for regular, beta, and patch releases
- Dropped extra zeros from version numbers to follow upstream more closely
- SRC_URI has been updated to the new upstream location
- Fixed dependency on CLHEP to require matching USE=threads
- Added USE=c++XX flags to allow users to choose C++ standard (this is
  useful for packages that depend on both sci-physics/root and geant
  to ensure that they have been compiled with matching C++ standards).
- New USE=hdf5 and USE=freetype have been added
- Removed obsolete scripts and unnecessary dependency on app-shells/tcsh
- Always use system's zlib instead of bundled one
- Removed usage of PDEPEND by updating geant-docs and geant-data
- Added patch to allow customization of CMAKE_INSTALL_DATADIR
- Added ${EXTRA_ECONF} to allow users to customize installation further
  without patching ebuild itself or using an overlay

Package-Manager: Portage-2.3.94, Repoman-2.3.21
Signed-off-by: Guilherme Amadio <amadio@gentoo.org>