Add examples of specialized shape views for CMS.
Simplyfiy grammar handling.

There was a bug in the dd4hep_add_test_reg function which was only taking into account the last dependency of a test when several were present.
On the way, dropped a double dependency in DDDB_clean_LONGTEST

also drop deprecated rootcling options

CMake: behave as before if BUILD_SHARED_LIBS is not defined. Needed for examples and DD4hep external packageS

CMake: add settings DD4HEP_BUILD_PACKAGES to chose which packages to build, DD4HEP_BUILD_EXAMPLES to build examples

it will be the responsible of the user to chose a working combination and order of packages
Use DD4hep::<Package> so that cmake will fail if required package was not enabled