DB/Spawns: correct respawn timer of gameobjects and creatures to 5 minutes instead of 2

* since we have dynamic spawns now we no longer have to wait for the corpse to despawn which means we can now use the correct default respawn time of 5 minutes

sql/updates/world/custom/custom_2019_10_23_00_world.sql

@@ -0,0 +1,2 @@
+UPDATE `creature` SET `spawntimesecs`= 300 WHERE `spawntimesecs`= 120;
+UPDATE `gameobject` SET `spawntimesecs`= 300 WHERE `spawntimesecs`= 120;