[Regen] Implement Per Second HP Regen for NPCs (#2086)

* Implement NPC per second regen

* Add hp_regen_per_second to ModifyNPCStat

* Take per second regen the rest of the way

* Add #npcedit hp_regen_per_second

* Add db migration

utils/sql/db_update_manifest.txt

@@ -432,6 +432,7 @@
 9176|2022_01_10_checksum_verification.sql|SHOW COLUMNS FROM `account` LIKE 'crc_eqgame'|empty|
 9177|2022_03_06_table_structure_changes.sql|SHOW COLUMNS FROM `pets` LIKE 'id'|empty|
 9178|2022_03_07_saylink_collation.sql|SELECT * FROM db_version WHERE version >= 9178|empty|
+9179|2022_04_30_hp_regen_per_second.sql|SHOW COLUMNS FROM `npc_types` LIKE 'hp_regen_per_second'|empty|
 
 # Upgrade conditions:
 # 	This won't be needed after this system is implemented, but it is used database that are not

utils/sql/git/required/2022_04_30_hp_regen_per_second.sql

@@ -0,0 +1 @@
+ALTER TABLE npc_types ADD COLUMN hp_regen_per_second bigint(11) DEFAULT 0 AFTER hp_regen_rate;