cpdb-backend-file 2.0b5

In the fifth beta release for cpdb-backend-file 2.0.0 we have removed the now unnecessary backend info file and fixed some bugs.

• Remove CPDB backend info file
  The frontend libraries now use only the D-Bus to find available backends. This makes sure that everything works also if the frontend and/or any of the backends are installed via sandboxed packaging (like Snap for example) where the components cannot read each other's file systems.
• Build system: Removed unnecessary lines in tools/Makefile.am
  Removed the TESTdir and TEST_SCRIPTS entries in tools/Makefile.am. They are not needed and let make install try to install run-tests.sh in the source directory, where it already is, causing an error.