Done in preparation for moving the script types to `primitives`.
The script types have a bunch of functionality to support scriptPubkeys,
and scriptPubkeys are an address thing.
Create a module under `address` and in it create a bunch of extension
traits to hold all scriptPubkey functionality.
Includes adding an ugly-as-hell macro to create the traits.
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.
Jamil Lambert, PhD
Tobin C. Harding
Divyansh Gupta
Jose Storopoli