Impl sub, mul and div for actual objects

[Cesar199999]

Should solve the reference hell in https://github.com/HungryCatsStudio/aurora/blob/core/src/aurora/mod.rs#L288

[Antonio95]

Very sorely needed, thanks. Maybe there's a reason why it wasn't implemented in Arkworks (maybe Marcin knows about it; avoiding cloning?), but the syntax it requires is a nightmare

[mmagician]

I'm not sure, maybe @Pratyush knows?

[Pratyush]

I think adding the APIs makes sense; I just hadn't added them because these versions move the input polynomials, so the caller will have to do a.clone() - b.clone() (for example).

[Cesar199999]

I'd say adding pass-by-value arithmetic shouldn't be too problematic since (1) it's already there for polynomial sum and (2) the user can still use the reference analogues if he doesn't want to consume the objects.

[mmagician]

@Cesar199999 probably worth adding upstream directly, then

[Antonio95]

Very cool! Not cloning or moving data.

[Cesar199999]

@Cesar199999 probably worth adding upstream directly, then

Sure, arkworks-rs#843