lowmem: Support 'get_kill_candidates_post' funcs

lowmem: Support 'get_kill_candidates_post' funcs

Support LMK governor post funcs which will be called after
LMK governor function to reorder a victim candidate list

resourced LMK needs to reorder victim candidates list according to
serveral conditions (e.g., working set size, foreground app status)

resourced supports three type of get_kill_candidates_post ops newly
  - int syscommon_plugin_resourced_memory_lmk_get_kill_candidates_post(
		  GArray *candidates)
  to consider user custom governor policy
  - int syscommon_plugin_resourced_memory_lmk_get_kill_candidates_post_with_wss(
		  GArray *candidates)
  to consider working set size of app
  - int syscommon_plugin_resourced_memory_lmk_get_kill_candidates_post_with_foreground(
		  GArray *candidates)
  to consider window information of app

Change-Id: I32bab160d66d05cd986b9f84c942ea1d2b8a59c4
Signed-off-by: Unsung Lee <unsung.lee@samsung.com>