Extend hardcoded weapon shaders & trace sfx overrides

[ividyon]

More wishlist stuff / "did you know this exists" stuff.

In SpEffectVfxParam, you can apply several fun things to your weapons:

traceSfxIdOffsetType

Lets you change the default weapon trails to Magic, Fire, Lightning etc.
How it works is as follows:

• Every weapon under EquipParamWeapon has traceSfxId entries, such as 401000. This is an FXR ID corresponding to a vfx file.
• The int under traceSfxIdOffsetType offsets this id by 10000 + ((traceSfxIdOffsetType - 1) * 1000).
• Example: You use a Fire Grease, which has a traceSfxIdOffsetType SpEffectVfx with value 2, which stands for Fire. Your weapon will now use 401000 + 10000 + ((2 - 1) * 1000) = 412000 as its swing trail.

This is cool, however traceSfxIdOffsetType is arbitrarily restricted to a fixed list of values. Other values have no effect, even if you add VFX at those IDs. This doesn't make much sense due to the otherwise very dynamic nature of the offset calculation.

Make it possible to enter an arbitrary number! That way we can create more trails whenever we want.

soulParamIdForWepEnchant

Lets you apply a PhantomParam-esque visual shader overlay to your weapon. For example, when you use Determination/Royal Knight's Resolve, your weapon glows white, like a Dark Souls cooperator.

This is, again, based on an enum which vaguely corresponds to the traceSfx ones, but only vaguely.

There does not appear to be any way to edit these phantomparam looks, nor to add additional ones. It's a hardcoded list of fixed looks. Again, this would be appreciated.