Merge branch 'develop' of ssh://stash.desy.de:7999/hidra2/hidra2 into feature/HIDRA2-13-access-detector-frames

* commit '55471c1a':
  fix build without testing
  test coverage

Added FileStatusEvent Struct

applied naming guidelines to producer

Merge pull request #3 in HIDRA2/hidra2 from feature/HIDRA2-22-creating-initial-file-structure to develop

* commit '5bc68558':
  Create initial sub-project structure

Added project strucre; some tests & first producer

changed folder structure

Made test build optional

Changed project structure for producer

added doxygen

added doxygen to cmake

fixed doxygen file

made googletest separated

changed cmake strucure

Added head lock guard