This commit is a follow-up to the discussion on bytecodealliance#6732. This removes
Wasmtime's implementation of the wasi-crypto proposal from in-tree along
with its various support in CI, configuration, etc. See the discussion
on bytecodealliance#6732 for the full information but at a high level the main reasons
for removing the implementation at this time are:

* There is not currently an active maintainer of the Wasmtime
  integration here for wasi-crypto.
* There are known issues with the code quality of the implementation
  such as transmutes of guest-owned memory to `&'static mut [u8]` and
  known unsafety in dependencies.
* The size and breadth of the dependency tree brings maintenance burden
  and overhead to managing Wasmtime's dependency tree.

As mentioned on the issue this commit does not mean that Wasmtime
doesn't want to implement the wasi-crypto proposal. Instead the "tier 3"
status of wasi-crypto needs to be re-attained to be included back
in-tree, which would mean resolving the above issues.

Note that this commit is intentionally just after the 13.0.0 branch
point which means that this is slated for Wasmtime 14 to be released on
September 20.