[FEATURE] Create a MovePicker

[dannyhammer]

Description:
A MovePicker is a tool that selects the next-best move available when called, regardless of what order the moves are in. It sorts moves one-by-one rather than all at once. The logic here is that, because we're likely to prune nodes after only a few moves, we shouldn't waste time sorting every available move. We should only expend computational power on sorting the moves we actually care about.

Relevant Link(s):

• Rustic Book on Move Ordering

Requirements:

• Implement a MovePicker
• Score all moves at once, then store moves along with their scores
• Make it implement Iterator maybe?
• Ensure that it gains!