Avoid multiple copies of bb.js being loaded

[spalladino]

Today aztec.js depends on both types and circuits.js, and types also depends on circuits.js. It can happen that npm or yarn decides to install a copy of circuits.js within aztec.js and another within types, in case there's already a circuits.js in the root of node_modules with a different version. This has led to serialisation issues (see #1826), and can lead to multiple copies of the circuits wasm being loaded, which can have an impact on memory usage.

We should explore whether removing the dependency from aztec.js to circuits.js (and instead having types re-export everything that's needed) would solve the issue. This also requires analysing all other dependencies to circuits.js.

[spalladino]

Updating the issue since this now may happen with foundation and circuits.js both importing bb.js