Move the addition of the FIT tag out of the item constructor.

As requested there: https://github.com/CleverRaven/Cataclysm-DDA/pull/9390#issuecomment-57915591

Moved the addition of the FIT tag to new items out of the item constructor. The probability is a always 1 in 3, crafted cloth is always fitted (was already that way), byproducts are also always fitted (new, but might not ever by relevant as fitting only applies to certain armor).

NPCs should have a slightly higher chance of fitted armor (at least the worn is probably fitted, new characters start with all cloth fitted), but this is not implemented. Their armor has the same chance as every other item to be fitted.

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There is however still a lot of randomness in the item constructor:

- left / right coverage of sided armor.
- random charges of tools / food
- vehicle parts with variable size
- random description (survivor notes)

What about those?