Added argument dim to JWST_in, was required by ProxOperators

Added ProxOperator P_amp

Added ProxOperator Approx_P_JWST_Poisson: still needs to be tested

Changed comments in JWST_in and deleted duplicate
Modified Phase_JWST_demo.py to test phase.py

JWST_data_processor is now using the right Resize function from Utilities, norm_rt_data now matches norm_rt_data from the matlab version,
but other values still need to be checked.

Continued fixing JWST_data_processor, but JWST_data_prcessor is still not working correctly

Moved and renamed phase test script script.py
Made some progress on JWST_data_processor

Added FFT in Utilities/Utilities.py , FFT was tested and should work like the equivalent in the ProxMatlab.
But there are still issues with row-major order vs. column-major order, therefore implementation might not be efficient.

This commit is the result of a history rewrite. Commit messages up to here may
not be entirely accurate, as they might refer to files that have been removed or
are now part of the other split repo (i.e. the Matlab version).

Changes include:

- Removal of *.mat from history
- Removal of generated files like *.pyc and Sphinx API reference
- Addition of .gitignore file
- Minor adjustments due to changed paths

*Not* included are modifications pertaining to references to the `inputdata`
directory, which is not, and should not be, part of the repository anymore. In
particular, the test suite fails in this commit due to missing input data. To
get a list of all source locations which have to be adjusted, use `git grep
inputdata`.