This PR sacrifices passing some extra arguments to get rid of the global
state.

* Haraka needs state in all hash calls, this results in changes to the
  hash functions specified in `hash.h`.  The extra pointers passed would
  not be necessary for SHA256 or SHAKE256.
* SHAKE256 did not have global state, but uniformity in the implementations
  requires us to pass  around the new state context anyway. Otherwise,
  @joostrijneveld's SPHINCS+ generator doesn't really work anymore).

We introduce a new header file called `primitive.h` which defines the
required state type for the generic functions. I did not go into
replacing _all_ occurrences of state variables by the new `hash_state`
macro.

Windows already complains about this in CI, but this will
let us catch these issues on Linux as well.

* fix prototypes for sphincs and static functions in aes.c

* fix missing prototypes in all frodo variants

* fix missing prototypes in kyber

* remove const from non-pointer arguments in Frodo

* add missing prototypes to requirements in README