In some applications, notably Inkscape, where it is common to frequently drag
objects a short distance the default to drag-lock always-on is frustrating for
users.
Make it configurable, with the current default to "on".
New API:
  libinput_device_config_tap_set_drag_lock_enabled
  libinput_device_config_tap_get_drag_lock_enabled
  libinput_device_config_tap_get_default_drag_lock_enabled

Any device capable of tapping is capable of drag lock, there is no explicit
availability check for drag lock. Configuration is independent, drag lock may
be enabled when tapping is disabled.

In the tests, enable/disable drag-lock explicitly where the tests depend
on it.

https://bugs.freedesktop.org/show_bug.cgi?id=90928



Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>