Currently we have a trait `Hash` that is required for `Hmac`, `Hkdf`,
and other use cases. However, it is unegonomic for users who just want
to do a simple hash to have to import the trait.
Add inherent functions to all hash types including those created with
the new wrapper type macros.
This patch introduces some duplicate code but we are trying to make
progress in the hashes API re-write. We can come back and de-dublicate
later.
Includes making `to_byte_array`,`from_byte_array`, `as_byte_array`, and
`all_zeros` const where easily possible.
In preparation for improving the `base58` error types crate an `error`
module and move the single current error type there. Make the module
public and reexport the type.
Add a new `base58` crate to the workspace and move the `bitcoin::base58`
module to it.
Done as part of crate smashing, specifically so that we can make `bip32`
into a separate crate.