Add global directory for simulation test inputs

Add global directory for simulation test inputs

Adds the ability to testfilemanager to use input files from a global
defined directory that is set at CMake time and contains the input files
for tpr file generation in the tests.

When a file is not found in the current directory, the code searches
the global archive for it and finally falls back to the current
directory if no file extension was given.

Example case is given for the tool test that needs a pdb and a top file.

Change-Id: Ic94f4a4d0d451024b435bf2900360aa60cd01b11