resourced-memory-lmk: Add a skeleton of get_kill_candidates_post funcs

resourced-memory-lmk: Add a skeleton of get_kill_candidates_post funcs

Add a skeleton of three get_kill_candidates_post funcs
(get_kill_candidates_post, get_kill_candidates_post_with_wss, and
get_kill_candidates_post_with_foreground) in resourced-memory-lmk

resourced supports three type of get_kill_candidates_post ops newly
  - int get_kill_candidates_post(GArray *candidates)
    to consider user custom governor policy
  - int get_kill_candidates_post_with_wss(GArray *candidates)
    to consider working set size of app
  - int get_kill_candidates_post_with_foreground(GArray *candidates,
		  enum oom_level oom_level)
    to consider window information of app

Change-Id: I9f774c6ff075f48319925c40c772c969ce838d03
Signed-off-by: Unsung Lee <unsung.lee@samsung.com>