SlimnessFS Policy Addition

Manual merge of !11048 (closed)

Mainly tweaking things to modifiers, mostly to better handle pregnancy breast growth, though lost a little of singles. Twins+ works better in exchange. Overall within reason, I say. Also needed player diet checks to make sure they'd actually be eating the revised food or not.

Dropped saAgent changes, mostly for simplicity. And because I couldn't figure out a good way to tag which arcology was hers to check for slimness there.

@svornost

I feel like I'm missing BC somewhere.