Extend blacklist/whitelist handling in Excess Inventory

[SteveTownsend]

Nexus DM suggestion

auto sell function: items marked like black/white list is sold at x% based on menu slider

Note that this is distinct from the autoloot blacklist/whitelist. My response:

For auto-sell - I've already added support for having items avoid Excess Inventory handling. There is a sample file that does this for AddItemMenu items, treating them as a blacklist which means (confusingly) "leave in Inventory". IU mmight switch the sense of this before extending so that this is 'whitelist' meaning 'always keep'. It would be then possible to add 'blacklist' handling to redirect all items of a given type to 'always sell'.