Add an `as_bytes` or `to_bytes` to the `String` type

[kalepail]

As far as I'm aware it's currently not possible to convert the String type into it's Bytes counterpart. This limits the usefulness of String significantly. Would love to see this feature added.

Discord context: https://discord.com/channels/897514728459468821/1201650246573367407

[Xand6r]

For anyone who later runs into this issue.

pub fn string_to_bytes(str1: String) -> Bytes {
    let env = Env::default();
    let str_len = str1.len() as usize;

    // how large should this buffer be?
    let mut slice: [u8; 100000] = [0; 100000];

    str1.copy_into_slice(&mut slice[..str_len]);
    Bytes::from_slice(&env, &slice[0..str_len])
}

[tupui]

Oh that would be handy! I needed this like now and this snippet works great. I just added some input validation in it to check for a max length of like 64.