feat(Core/CreatureAI): improve npc position during the combat (#3369)

+ tangent equation to find correct angle and distance when moving

+ implemented proper backward

* Improved performance + random angle margin

* chore: add tollerance calculation in instance

* improved LOS checks with movements

* implemented collisions using raycast (imported by TC)

+ improved collision detection for CanReachPositionAndGetCoords

+ improved collision check

+ set correct flags for the backward movement

+ first implementation of slope angle (to improve)

Co-authored-by: Yehonal <yehonal.azeroth@gmail.com>

src/server/game/Spells/SpellInfo.h

@@ -437,6 +437,7 @@ public:
     bool IsPositive() const;
     bool IsPositiveEffect(uint8 effIndex) const;
     bool IsChanneled() const;
+    bool IsMoveAllowedChannel() const;
     bool NeedsComboPoints() const;
     bool IsBreakingStealth() const;
     bool IsRangedWeaponSpell() const;