[core] start integration of the process

• core
  • create the four main processes: normalization, Fourier transform, k weight definition and exafs
  • create simple input and putput process for loading spectrum and configuration and dump them (into a .h5 file)
  • add unit test for those process
• workflow
  • allow to create workflows from those core processes
  • test simple workflow creation and execution
• orange
  • create raw interfaces in orange for the four process + io
  • keep settings to be able to tune the xas process
  • allow user to convert a .owls file into a 'xas' workflow and process it.
• add CI
• add tutorial
  • add CI for the tutorial
• add application to convert from an orange workflow file (ows) to a non gui process.
  • using only the settings contained in the workflow file.
  • add option to give an input file and an output file:

      ./bootstrap.py xas process pymca_workflow.ows -i /usr/share/pymca/EXAFS_Cu.dat -o ./output.h5

  In this case the file settings are patch before the execution.