Allow to craft some items with filthy parts

# Is your feature request related to a problem? Please describe.
Craft system refuses any filthy item, so filthy rags/felt/lether patches/fur pelts are not allow to be an ingredient.
However some item like Molotov and weapon are supposed to be OK with a filthy part, as it is prone to be filthy again or burnt soon.
And they're not worn on a body, there's no risk of being infected or bad morale.

# Describe the solution you'd like
Introducing a flag check `ALLOW_FILTHY`, like `lamp_oil` did(#29770). To Allow it being crafted with filthy item.

# Describe alternatives you've considered
Also considering remove `rag_bloody` item, as it was a remnant before filthy system introducing.

# Additional context

Review the existing lamp_oil ALLOW_FILTHY implementation referenced by #29770 and identify the crafting definitions for filthy rags, felt, leather patches, and fur pelts. Confirm which Molotov and weapon recipes should accept them, then verify the affected crafting behavior and decide separately whether rag_bloody is still needed.

Written by the indexing model from the issue text.