Support borrowed deserialization with serde

[SzczurekYT]

With serde it is possible to for have a struct like this one

struct Foo {
    bar: &str
} 

and deserialize it, where the string borrows from the bytes.
But that doesn't work with CrabNBT

[PonasKovas]

nbt strings are not necessarily valid utf8 and cant be just borrowed from the bytes like this as they might require conversion