Allow the Thief Lockpicking to be granted by a Blursing

[markyys]

This is a superset of #977 which turns the "Thief Lockpicking" checkbox into a select list with the options "None" (same as unchecked before), "Thief" (same as checked before), and "Blessed Thief Only" (adds a bonus to the pool which can be applied to Thief. If present, it grants the lockpicking ability). If this is merged then #977 should be closed, as it will have been superseded.

Because of how I structured this we could easily allow any class to pick locks simply by adding it to the list of classes which can obtain this bonus.

I built the application, deployed locally, and tested various scenarios (no Thief, Thief but in None mode, Thief with no bonus in Blursing mode, and Thief with bonus in Blursing mode). Everything matches my expectations, and all behavior appears to be correct.

I welcome all comments, feedback, and corrections. This is the first time I've done any 6502 programming.

This impacts #964 which I think gets easier to implement if this is merged first.