[Feature Request] Allow filtering by item lock state

[philkernick]

I have a large number of armor pieces that I have for infusion purposes. I never want to include them in a loadout. All of my armor for infusion are unlocked, and all of the armor that I use is locked.

This also tracks the automatic lock state that DIM implements.

Request:
Add another button in the Armor Selection section:
Include only locked items (default off to not break backwards compatibility)