Implement traits of external crates

[daxpedda]

We discussed implementing this for Zeroize for example, this might not be necessary if Zeroize can be fixed with a PR.
We should explore this further.

[ModProg]

While 3rd party crates can be fixed via a PR, this adds a new syntax for each crate, so being able to do it with a standard way might be interesting in itself, the only issue is that that adds more traits to maintain which could be unstable.

[daxpedda]

We probably will need to implement something like this too then:

• #[derive_where(Zeroize(drop)] à la #[zeroize(drop)]
• #[derive_where(Zeroize(crate = "zeroize_")] à la #[serde(crate = "..."]