feat: add Borsh

[Cifko]

Add Borsh(De)Serialize for keys and signatures.

[stringhandler]

This also needs to be behind a borsh feature, as I mentioned in tari_utilities

[CjS77]

This also needs to be behind a borsh feature, as I mentioned in tari_utilities

+1 on this

Will have to use a pattern similar to:

use std::fmt::{Debug, Display};

pub struct Foo<T> {
    bar: T
}

impl<T> Foo<T> 
where
 T: Debug,
 {
     pub fn baz(&self) {
         print!("{:?}", self.bar)
     }
 }
 
#[cfg(feat)]
impl<T> Foo<T> 
where
 T: Debug,
 T: Display, 
 {
     pub fn baz2(&self) {
         print!("{}", self.bar)
     }
 }

[CjS77]

lgtm

[sdbondi]

I think having a different trait depending on whether the borsh feature flag is enabled or not could be troublesome.

Any reason we require these trait bounds in the trait itself? They can always be specified where needed.

[sdbondi]

Suggest these changes:
crypto.diff.txt