[Examples] examples folder cleanup

[wiktor-flex]

• removed deprecated examples
• removed data/ folder with unused assets
• adjusted case_from_multiple_files/ folder's example
• adjusted change_account_and_submit.py
• adjusted project_from_file_geometry_multiple_runs.py -> generate_multiple_meshes.py
• adjusted run_case_unsteady_from_files.py -> 2D unsteady cylinder and 3D unsteady cylinder examples
• adjusted run_case_with_fork.py
• adjusted show_storage.py -> storage_list.py
• submit_case_to_folder.py

run_case_with_retry.py remains unchanged since there I didn't find functionality in V2 that can produce the same effect and using a mix of V1 and V2 also didn't work, it is up to debate what to do with it