[MEDIUM] Fix memory freeing at exit

[MEDIUM] Fix memory freeing at exit

New functions implemented:
 - deinit_pollers: called at the end of deinit())
 - prune_acl: called via list_for_each_entry_safe

Add missing pool_destroy2 calls:
 - p->hdr_idx_pool
 - pool2_tree64

Implement all task stopping:
 - health-check: needs new "struct task" in the struct server
 - queue processing: queue_mgt
 - appsess_refresh: appsession_refresh

before (idle system):
==6079== LEAK SUMMARY:
==6079==    definitely lost: 1,112 bytes in 75 blocks.
==6079==    indirectly lost: 53,356 bytes in 2,090 blocks.
==6079==      possibly lost: 52 bytes in 1 blocks.
==6079==    still reachable: 150,996 bytes in 504 blocks.
==6079==         suppressed: 0 bytes in 0 blocks.

after (idle system):
==6945== LEAK SUMMARY:
==6945==    definitely lost: 7,644 bytes in 137 blocks.
==6945==    indirectly lost: 9,913 bytes in 587 blocks.
==6945==      possibly lost: 0 bytes in 0 blocks.
==6945==    still reachable: 0 bytes in 0 blocks.
==6945==         suppressed: 0 bytes in 0 blocks.

before (running system for ~2m):
==9343== LEAK SUMMARY:
==9343==    definitely lost: 1,112 bytes in 75 blocks.
==9343==    indirectly lost: 54,199 bytes in 2,122 blocks.
==9343==      possibly lost: 52 bytes in 1 blocks.
==9343==    still reachable: 151,128 bytes in 509 blocks.
==9343==         suppressed: 0 bytes in 0 blocks.

after (running system for ~2m):
==11616== LEAK SUMMARY:
==11616==    definitely lost: 7,644 bytes in 137 blocks.
==11616==    indirectly lost: 9,981 bytes in 591 blocks.
==11616==      possibly lost: 0 bytes in 0 blocks.
==11616==    still reachable: 4 bytes in 1 blocks.
==11616==         suppressed: 0 bytes in 0 blocks.

Still not perfect but significant improvement.