Added option to order by last update time in the experiment search results windows. Added update time in the experiment item component

Replaced the pkl update procedure of the Tree Representation. It now implementes an objected oriented solution with its own tests. Fixed tests

Working on a clean and testable implementation of the Tree Pkl Update procedure. Updated README to remove unnecessary index item.

Fixed bug with job history for jobs that have an exception in the history retrieval process. For example, when the run doesn't exist anymore.