New User Agent handling #15392

See https://groups.google.com/a/chromium.org/forum/m/#!msg/blink-dev/-2JIRNMWJ7s/yHe4tQNLCgAJ

and https://wicg.github.io/ua-client-hints/ which makes it possible to still get some information.

All major browsers seem to be "freezing" the user agent and will remove certain information from the user agent for privacy reasons etc. If someone wants more details, then client hints will be needed. Here is an example: https://wicg.github.io/ua-client-hints/#examples It may need additional requests basically if I see this right. There will also be a new getUserAgent method.

There will be some restrictions like Client Hints will not be delivered to non-secure endpoints.

closing this one as duplicate of https://github.com/matomo-org/matomo/issues/16125