Finer-grained integration with the wccargo website

The ruleset `com.wccargo.html` currently has a copy of all of the HTML/CSS/JS code from the wccargo website.

This gives a dependency between this project and that website. Whenever the latter evolves, that ruleset must be brought into agreement.

Ideally, the website page at https://wccargo.com/tracking.html would be modified to use AJAX to request a JSON response from the pico and fill in a `

` tag with the order updates. This would make the `com.wccargo.html` ruleset redundant and instead of returning HTML, the `com.wccargo.tracking` ruleset would return a JSON object (a String actually) to the adapted website page.

Start by reading the com.wccargo.html and com.wccargo.tracking rulesets alongside tracking.html on wccargo.com. Trace how the current page and ruleset exchange tracking data. Done means the page requests JSON, displays the order updates in its pre element, and the duplicated com.wccargo.html ruleset is no longer needed.

Written by the indexing model from the issue text.