[orange-add-on] Add possibility to load configuration from .hdf5 in the input widget

See merge request workflow/xas!3

Keep configuration when non gui processing

Closes #2

See merge request workflow/xas!2

- create callable classes in order to get the setParameters function.
- copy parameters to the xas_obj processed.
- /close #2

[core] start integration of the process

See merge request workflow/xas!1

[io] rework spectrum, to separate exafs and FT. Should even be other variable. Update the output configuration

- we can convert .ows to a gui free workflow.
- user can give input and output file to overwrite the one existing in xas.

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

[unit test] add a workflow unit test with the four first process. Should ne executed without any log error from pymca

[orange add-on] Add information about the function to process in xas.core.process for each widget `process_function`

Sould include the xas process, then how to define a workflow of those process and then how to mode from onw orange workflow definition to a gui free processing.

[orange add-on] add some curves to be displayed during xas processing. Xas widget should embed there own plot