Block and critical formulas implementation

[kenedos]

This PR implements:

• [NEW] Block Rate
• [NEW] Block Penetration
• Block Chance Formula
• Block damage reduction (50% less damage)
• [NEW] Critical Defense Rate
• Improved Critical Chance Formula
• Improved Critical Damage to deal 1.5x damage
• Adds Block/BlockPen and Critical Attack/Rate/Defense stats for monsters

This PR DOES NOT implement:

• Active blocking (holding 'C' to block)
• Equipment block rates in items.txt database

Videos:

• Player blocking attacks: https://www.youtube.com/watch?v=tGhd0X7mmpM
• Monster blocking attacks: https://www.youtube.com/watch?v=IcUwUen4OZA

Based on: https://treeofsavior.com/page/news/view.php?n=951 Credits to @SalmanTKhan for base implementation