[FEATURE] Improve attack automation

[Eranziel]

Add automation in the attack flow/HUD to modify the attack roll accordingly for each of these conditions:

• Stunned. Target's defenses should be lowered.
• Prone. Attacker gets +1 accuracy.
• Engaged. Ranged attacker gets +1 difficulty.

[BoltsJ]

Stunned could be handled by adding ActiveEffect change data to the object for it in CONFIG.statusEffects, though I don't know how well that plays with our status builder functionality.