elm_focus: added new focus move policy and elm_object_focus_move_policy_set/get

elm_focus: added new focus move policy and elm_object_focus_move_policy_set/get

New focus move policy, ELM_FOCUS_MOVE_POLICY_KEY_ONLY, is added.
If you set this policy as base focus move policy, objects cannot steal
focus by using mouse click or mouse in. Only keyboard input (such as Left,
Right, Up, Down, ...) can make focus be moved.
Additaionally, an object can have its own focus move policy by using
elm_object_focus_move_policy_set API.

@feature

Change-Id: Iaa64ce2e92b2a376d000907e2986873fa542e655
origin: upstream