Depreciate `squin.qubit.broadcast`?

[jon-wurtz]

The interface is unclear (weird strides in the list that depend on the qubit number) and overlaps with a for loop:

controls:list[Qubit] = ...
targets:list[Qubit] = ...
op:Op = ...
for c,t in zip(controls,targets):
    squin.qubit.apply(op,c,t)

# equivalent to
register:list[Qubit] = interleave(controls,targets) #lol how do you do this actually? Where the evens are controls and odds are targets
squin.qubit.broadcast(op,register)

[weinbe58]

I'm broadly in favor of rethinking broadcast semantics, it overlaps too much with Apply. I was thinking something like:

controls:list[Qubit] = ...
targets:list[Qubit] = ...

broadcast(h(), [targets])
broadcast(cz(), [controls, targets])
broadcast(h(), [targets])