Automatic compilation of mptwitness (privacy-scaling-explorations#1605)

### Description

The PR adds the mpt-witness-generator into the workspace, and
automatically bulding the go library via rust.

### Type of change

New feature (non-breaking change which adds functionality)

---------

Co-authored-by: adria0 <adria0@nowhere>

Author: adria0

Cargo.lock

@@ -9,7 +9,8 @@ members = [
     "eth-types",
     "external-tracer",
     "mock",
-    "testool"
+    "testool",
+    "mpt-witness-generator/rustlib"
 ]
 
 [patch.crates-io]