Resolve "Export Histograms to plain root file in analyze"

Release notes

Added an options to write out histograms into a plain root file:

  - exportHistograms.path: path to the plain root file to export to
  - exportHistograms.fileName: file name of the plain root file to export. Path and file name are split in two options for easier batch processing
  - exportHistograms.processes: process definition file as used for visualize (plotter, cutflowprinter, ...)
  - exportHistograms.channels: comma separated list of channel names, individual names are defined in the channelConfig file
  - exportHistograms.channelConfig: path to config file defining channels (identical to visualize channel config file)

Details

Closes #292 (closed)