Add a MoveInfo parsing proxy between SidePanel and MoveTreeDisplayHandler

[hexaquarks]

MoveTreeDisplayHandler currently returns an std::vector<MoveInfo> through generateMoveInfo(). This struct is generic in that it has no UI-related specifications. It only indicates the row, indent, content, etc., of the move that shall be displayed on the SidePanel. When we draw the side panel, ideally, the process would be const but it currently isn't because of drawMoves() which is a non-trivial process in itself.

In this task, I want to inject a proxy that would take the std::vector<MoveInfo> and output an std::vector<MoveInfoDisplay>. Here MoveInfoDisplay is a struct that holds a reference to MoveInfo but also has the necessary information to draw the move, i.e., position, dimensions, etc.

With this, we could do SidePanel::draw() const { drawMoves(); /* ... other const draw methods */ }
#66