Use the more terse `hashes` by way of the `package` field in the
manifest.
Allows us to remove the ugly feature alias "bitcoin-hashes" ->
"bitcoin_hashes" and removes all the bother with the underscore.
Why did we not think of this 2 years ago?
The `wasm-pack` command does not honour `cargo` flags passed to it so we
cannot use `--locked` and test against pre-made lock files. Instead just
run the WASM test from the test script wrapper.
We would like to be able to run the test script with different lock
files, in preparation for doing so move the `test.sh` script to
`_test.sh` and add a new `test.sh` that runs `_test.sh`.
Keep the outer script as `test.sh` so that we do not change the workflow
for those running the script including the github actions.
Tobin C. Harding