Enhance "autosubmit stats" summary and plot to present load balance metrics and other performance values

To introduce an enhancement in Autosubmit to have the load balance data and other Lucia output to be included in the stats plot. The modification proposed is just to add a new file handled by Autosubmit in a dictionary format as a container of different values computed during the workflow. The autosubmit stats command can read and present the keys and values in the text and pdf summary.