Update NNUE architecture to SFNNv14 and net nn-7bf13f9655c8.nnue
[STC](https://tests.stockfishchess.org/tests/live_elo/69cb991bc025c305b7daa219)
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 47520 W: 12558 L: 12219 D: 22743
Ptnml(0-2): 190, 5474, 12102, 5795, 199
[LTC](https://tests.stockfishchess.org/tests/live_elo/69cc6b42731dfb72d2e92128)
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 123756 W: 31996 L: 31497 D: 60263
Ptnml(0-2): 81, 13512, 34221, 13955, 109
Adds features for pawns pushing against other pawns. For indexing, we
use the existing threats feature set by adding the forward square to the
squares threatened by a pawn. This threat is only enabled when another
pawn occupies that square. We then add appropriate logic changes in
`update_piece_threats` and `features/full_threats.cpp`.
The wonderful Ciekce (of Stormphrax) and peregrine (of Reckless) also
had similar ideas with adding forward pawn movements to TI, and I
appreciate their giving me motivation to figure out `nnue-pytorch` and
test it.
closes https://github.com/official-stockfish/Stockfish/pull/6694
Bench: 2926703