elementary: add new config value to handle tap finger size.

elementary: add new config value to handle tap finger size.

Summary:
The tap_finger_size value of the concept is different from the finger_size value used in the past.

We need a minimum value for recognize the gesture as a tap or not.

Since the actual screen has different screen sizes, there is a problem that the recognition rate of tap is lowered when using the existing value(finger_size)

Test Plan: elementary_test -> gesture sample.

Reviewers: cedric, woohyun, Jaehyun_Cho, herb, id213sin

Subscribers: cedric

Differential Revision: https://phab.enlightenment.org/D5842

Reviewed-by: Cedric BAIL <cedric@osg.samsung.com>
Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>