Support arc4.StaticArray empty constructors

[tristanmenzel]

Given a static array of a size and type

MyArray: typing.TypeAlias = StaticArray[Address, typing.Literal[2]]

There should be an empty constructor

my_value = MyArray()

that is the equivalent of initializing the array with N items, initialized via their empty constructor

MyArray() == MyArray(Address(), Address())

This should recurse for nested static arrays