Compile glean-core to WASM experiment

I did not have success compiling the whole thing to WASM, but I was able to compile the histograms part and try it out in the distributions simulator.

This repo is the result of that.

How to build

Inside the src/ folder is where the Rust code lives. To build it, run:

wasm-pack build

This will generate a pkg/ folder inside the root folder of this project. Run:

cp -f -r pkg/ site/glean/

This will copy that folder to the site/ folder which contains the simulators code.

If you look inside site/package.json you'll see that we include the code generated by wasm-pack build as a dependency to our JavaScript project.

Now go inside the site/ folder and run:

npm run dev

Open http://localhost:3000 to see the result.