HUD hit indicator

Implement a 2d directional hit indicator (enabled by default) around the screen center when a player hits you:

• up to 10 indicators at the same time
• the higher the damage, the bigger the indicator size
• damage is accumulated
• damage text can be displayed together with the hit indicator (disabled by default)
• hidden when the attacker is not visible
• disabled if chase_active is enabled
• shown while spectating a player too
• implemented as an extension of damagetext (requires sv_damagetext >= 2, default value is 2)

Extra:

• Make work damage text with the Vaporizer outside of Instagib
• added cl_damagetext_received (disabled by default) that allows displaying damage text when you receive damage too