Disable the installtion of gtest. It is currently not working and is also
not needed.

Add missing symbolic links which are needed during installation.

Define CMAKE_INSTALL_LIBDIR explicitly. In newer FairRoot versions the variable
is needed to setup the proper LD_LIBRARY_PATH for the CbmRootConfig macros.

When installing CbmRoot using FairRoot v18.4 and FairSoft there was a problem
with the location of header files when executing macros. Some of the header
files couldn't be found which for some of them worked with printing warning
or error messages only. For other header files the macros simply crashed with
error messages about not found header files. It is unclear if this is a
FairRoot or Root issue but I would guess it is a Root problem.
The issue was solved by simply removing the path from the header file name when
generating the Root dictionary. In this case it is enough to specify the
directory where all header files are installed when running Root using the
environment variable ROOT_INCLUDE_PATH.

In some of the build system files missing directories where added such that
the dictionaries could be produced properly.

To fix the tests for these macros, the Trd parameters need to be loaded from the
ascii file db. Since, during the tests no par.root file from the unpacking is
available

Remove the original file, which was outdated
Adjust name to match CbmSetup naming scheme
Adjust .gitignore to not ignore this explicit .root file

Trd clusterfinder and hit reconstruction tasks added to the common macros
No additional eventbuilding cuts based on the Trd where introduced