Add plot filter file

[DanicaSTFC]

Describe your changes

• Add file in the script folder to plot the filters.
• [ ] Add unit test in file https://github.com/TomographicImaging/CIL/blob/31877b010d2e18c6e04fe330cab6a3d3fff1ce10/Wrappers/Python/test/test_reconstructors.py

Examples of maplotlib testing: https://matplotlib.org/devdocs/devel/testing.html#writing-an-image-comparison-test

Describe any testing you have performed

Please add any demo scripts to CIL-Demos/misc/

Link relevant issues

#1666

Checklist when you are ready to request a review

• [ ] I have performed a self-review of my code
• [ ] I have added docstrings in line with the guidance in the developer guide
• [ ] I have implemented unit tests that cover any new or modified functionality
• [ ] CHANGELOG.md has been updated with any functionality change
• [ ] Request review from all relevant developers
• [ ] Change pull request label to 'Waiting for review'

Contribution Notes

Please read and adhere to the developer guide and local patterns and conventions.

• [ ] The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CIL (the Work) under the terms and conditions of the Apache-2.0 License.
• [ ] I confirm that the contribution does not violate any intellectual property rights of third parties