Jquery update

Bump tablesorter version to 2.3.0 Tablesorter only requires jquery 1.2.6+ which is long deprecated. I've updated deprecated functions in Tablesorter and raised the required version to jQuery 3.5+ Updated deprecated jquery functions in toolbar.js as well. I'm sure there are more but I've cleaned up the obvious ones that seem to be throwing most console warnings. https://github.com/pallets-eco/flask-debugtoolbar/issues/281 fixes #281