Enh: preserve change_ids within a session and beyond

[LukasGold]

Idea

• The functions / methods store_entity and upload_file return an object that has a change_id property
• It would be neat to have an attribute of OSW/OswExpress that collects all change_ids of applicable processes
• A context manager or a function decorated with @atexit.register from atexit would be required for implementation
  • At exit, the change_ids could be printed to the console
  • At exit, a file could be created, documenting the session with start and end time and list the change_ids.
    • The start time could be the file name
    • The default location for such a file could be the osw_files directory

At the moment change_ids can be collected and preseved like this:

stored = []
# Storing an entity requires only one line:
res = osw_obj.store_entity(john)
# But to be able to access all storage event later on, we will append the result to the list
stored.append(res)
change_ids = [res.change_id for res in stored]
with open(filepath, "w", enconding="utf-8) as file:
    file.write({
        "session_start": timestamp1,
        "session_end": timestamp2,
        "change_ids": change_ids
    })

This is rather lengthy and must be considered before making changes to an OSL instance