Add a method in Moves to produce chess strings

A pawn moving from
```
Move {
initial_square: 12,
target_square: 28,
},
```
shall produce "e4"

Maybe worth it to check what UCI expects... e4 vs e2e4 or some weird shit

Start by locating the Moves type and its Move fields, then check the UCI format expected for chess moves. The work is done when the example move from square 12 to square 28 produces the agreed string, such as "e4" or the corresponding UCI form.

Written by the indexing model from the issue text.