[libinput-touchpad-kcm-click-method] Add click method Areas and Clickfinger...

[libinput-touchpad-kcm-click-method] Add click method Areas and Clickfinger for buttonless touchpads

Summary:
- Added Properties to wayland Backend
- User can switch between areas and clickfinger methods if touchpads has no physical buttons.
- when areas mode is selected, user can enable and enable/disable middle-emulation.
- In clickfinger mode , for informative purposes checked but disabled checkbox will be shown with "Press anywhere with three fingers" text.

FEATURE: 387156
FIXED-IN: 5.16.0

Reviewers: ngraham, #plasma, romangg, davidedmundson

Reviewed By: ngraham, #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D18912