Make it easier to flop `LogicArray`s and `LogicStructure`s

[mkorbel1]

Motivation

The flop function and FlipFlop module flatten structures and arrays to a single packed Logic. If you want to flop an array or a structure, you may often want it to be an array or structure on the way out as well.

Desired solution

For API consistency, we could keep flop and FlipFlop, but update the input and output port creation to use LogicArrays when possible. However, this still would require a cast as LogicArray on the outputs.

Another new API might be a good idea: adding a .flop API onto Logic itself. Then, you could do things like

myLogic.flop(clk, ...) // returns a Logic
myStruct.flop(clk, ...) // returns a LogicStructure
myArray.flop(clk, ...) // returns a LogicArray

This way, the type could be maintained. Under the hood, it can just use the clone method, which already may be properly overridden by users with custom types of structures.

Alternatives considered

Currently, users have to do something like

myArray.clone()..gets(flop(clk, myArray,...));

Additional details

No response