Added Adaptive ADMM Showcase

[ljlozenski]

Describe your contribution

Added Adaptive ADMM Showcase for new functionality of Linearized ADMM added to cil

Checklist when you are ready to request a review

• I have performed a self-review of my code
• I have created a new folder, containing my contributions which are in the form of jupyter notebooks, with any necessary supporting python files, and a LICENSE file.
• I have added a description of my contribution(s) to the top of my file(s)
• If publicly available, I have added a link to the dataset used near the top of my file(s)
• I have added the CIL version I ran with near the top of my file(s)
• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CIL-User-Showcase.
• I confirm that the contribution does not violate any intellectual property rights of third parties.
• I confirm that I have added license headers to all of the files I am contributing (with a license of my choice)
• Change pull request label to 'Waiting for review'

Note: for an example of a contribution, where a license header, description, data link and CIL version has been added, please
see: example_contribution