finding dependencies with cmake should print warnings about incompatible versions (was ACTS-290)

Original author Christian Gumpert @cgumpert

So far, ACTS followed the strategy that in case an optional dependency was not found, the dependent packages/plugins where excluded from the build. A warning for excluded packages was printed.

The {{find_package}} cmake call was using the {{QIET}} argument to reduce the cmake output and because we would get a functional configuration with a few disabled packages. However, in some cases one wants to get a specific optional component installed and it would be really helpful to know why a dependency could not be found (e.g. due to incompatible versions). Therefore the {{QUIET}} argument to the {{find_package}} calls should be removed.