Fix no_std and add CI check

[pinkforest]

As is established standard in curve25519-dalek and fiat-crypto

[pinkforest]

@bwesterb I fixed Cargo manifest to make sure it doesn't break no_std and uses the resolver that is used by default with workspaces which we're used to - but this crate didn't use workspace so it was implicitly using resolver ="1" that caused it to bring getrandom even when only building - which broke no_std support.

It seems kyber1024 feature is broken - I'll mark it ignored for now

• kyber1024: ref polyvec.rs mismatched types #3

[bwesterb]

Thanks for this, and please accept my apologies for the late review. I saw it, and then completely forgot about it.

[bwesterb]

Had to revert because of build failure

error: `#[panic_handler]` function required, but not found

error: unwinding panics are not supported without std

[bwesterb]

Removing all panic! didn't work. Probably some panics in dependency?