Create concept for Active Effect implementation

[Re4XN]

Before an implementation of Active Effects can take place, a solid, generic concept / blueprint for their implementation should be created. Below is a list of examples of different Active Effects that might exist in the Zweihänder system:

• Litany of Hatred: -1 to DTh and PTh. This is the simplest form of Active Effect and has already been implemented as a PoC. No difficult concept or special cases need to be thought or implemented for this kind of Active Effect.
• The Full Monty: Skill Ranks in Charm modify Base Chance by +20 instead of +10. On the surface this looks straightforward: it is a simple override of the bonus granted per rank of the skill, e.g. item.system.bonusPerRank = 20, but it is actually quite complex because this bonus is attached to the skill Item, and Active Effects cannot, by default, modify Item data. Certain solutions can be implemented, such as 1) ditching Active Effects and implementing a custom Effects solution; 2) modifying the existing Active Effects to somehow support modifying Item data or; 3) do not use Effects for this at all and instead store the bonus value in a modifiable field on the Item sheet, accessible to the users.
• A Mind of Its Own: Treat Skullduggery as a common skill. Similar to the above point, this requires modifying Item data. Alternatively, the field for setting a skill as special is already implemented, merely requiring a way for users to access the skill Item sheet again.
• Hard to Kill: When Grievously Wounded, add 3 to DTh. This is a conditional effect and would require custom logic to implement if we want it triggering automatically. Otherwise, it can be triggered manually and becomes a simple addition akin to the first point presented in this list.
• Gatecrasher: _When you Take Aim and make a successful attack, add 3 to damage. _Similar to the above point, but in addition to being a conditional effect, it is only relevant when an attack roll is made. A tag should be assigned to this type of effect, so that it is displayed during the skill test configuration menu and can be taken into account by the user. Since damage is also part of an Item's data, we run into the previously discussed problem, although to be fair this +3 modifier can be an extra bonus added to the test configuration instead of modifying the attack roll formula then reverting it.