Better split and structure the annotation processing stuff

[andreaTP]

Moving the annotation processing stuff under a host-module sub-module.
Including the renames etc.

[evacchi]

I don't have much to add 🤔 the one single silly thing I am not really sure about is the package name host.module (because I'm thinking about what could end up under host), but it's not a big deal and I'm fine with it otherwise.

[andreaTP]

I'm not attached to the package name, I'll happily apply any proposed alternative 🙂

[electrum]

I also dislike the naming. Using a single lowercase word hostmodule seems to match common practice. This is really just a compound word, not a hierarchy.

What do you expect to call the WASM side of this? wasm-module?

[andreaTP]

What do you expect to call the WASM side of this? wasm-module?

I have an ongoing discussion with @evacchi on it, and progress on it already got stuck on naming a few times 😅