Inconsistent (and unneeded) use of of javascript for URL generation

[otheus]

In the javascript portion, the URL is dynamically generated. This seems rather silly given that in the section, the Image-tracker URL is hard-coded with these values. Simply generate them in PHP.

I also wanted to argue that the prefixing with 'http' or 'https' is obsolete for 15 years, when RFC 1808 was written. It specifies that //pwiki-trackerhost.org/piwik.php will work in any modern web-browser. However, this is not true for emailed or saved HTML pages. A page that is viewed in Outlook will not have a protocol context. Thus, the image-tracker should probably always use a configured or configurable fallback.

[gruniversal]

The current code expects matomo to run on the same webserver. This might not be the case so figuring out the protocol in php or js might give a wrong answer. Maybe it is easier to just define a complete URL instead of one without protocol.

That's what I would expect from $wgMatomoURL anyway, since it's called "URL" which includes a protocol.

The dynamic protocol version in the original code is only necessary when we don't know, which protocol is used.