[Proposal] snarkvm-algorithms: don't include aleo-std if CUDA is not enabled

[MauroToscano]

💥 Proposal

algorithms/src/lib.rs always uses aleo_std, but it's only needed when CUDA's feature is enabled

Conditional compiling can be used to avoid compiling aleo-std here when it's not needed, as well as the inclusion of the crate in Cargo.toml

[raychu86]

Should be addressed with https://github.com/ProvableHQ/aleo-std/pull/4