Implement logging capabilities (was ACTS-90)

Original author Christian Gumpert @cgumpert

It should be possible to redirect the logging output from ACTS objects to the logging facilities of processiuing frameworks (e.g Gaudi). A default logger should be implemented for use in standalone programs (e.g. for examples or testing). The logging code should be minimal invasive for the developer and the code. It should have the smallest possible effect on performance (e.g. only stream after check of logging level).