New WT component box: start-to-latest (with bodyfat % change)

[lbdsgn]

For the main graph display, the components: https://docs.yeken.uk/components.html

similar to the [latest-versus-target] one, rather than "Latest vs Target" my clients want a "Start to Latest" component with percent change showing. My clients want to display their progress to date, not their distance yet to go.

It's much more motivating to see your progress to date, than to see the distance you have yet to travel.

thank you