Rework DN to allow all skills

[farling42]

The function individualDN has a long list of permitted target... values (in CONFIG.torgeternity.dnTypes)

This should be converted to support any attribute, any skill, and any defense.

It should probably also use the attribute assigned to the skill for the Actor, rather than assuming specific attributes for each skill.

[farling42]

All target skills/attributes appear in a single drop-down menu in the Item sheet.
This would have to be changed to multiple fields - not so convenient to the user.