WP 6.6, WP Admin: updated GPX Track filtering, JS Updated, PHP Bug-fixing

Update chart.js, swiper.js and gpx.js to latest versions.
Minor PHP Bugfixes, e.g. updated focal length extraction for full-frame cameras.
Code refactoring of JS-common functions to libs started. Async loading started but not finished yet, and with no effect.
Added Functionality to Admin - GPX-Tracks: Waypoints are now copied to the filtered file. (But Routes still not). The Tracks are still combined to one track. Routes are still ignored.
Preparation of coloured Multi-Sport tracks still in code, not finalized and deactivated.

No Upgrade required. Only if you want the new GPX-Track filtering.