Also a long-requested configuration option but it's difficult to expose
- depending on the touchpad we utilize different palm detection methods
and in theory may add to those at any time as we see fit.
Disabling it completely via a configuration option is only going to get
us more bug reports because *some* palm detection is likely desired on
most setups. So let's allow disabling it in a plugin and thus leave any
further palm detection code up to the plugin.
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1249>
Over the years we had a few devices that required some special
hysteresis handling - all of it very customized to the device and not
upstreamable (or even implementable by upstream without the device).
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1249>