Added WebAssembly features

[MendyBerger]

Resolves mdn/browser-compat-data/issues/5796

Thanks @queengooborg for the new structure, it's a lot easier to make sense of the repo now.

Basic structure:
Added the wasm-feature-detect library, and testWasmFeature to the global bcd object.
testWasmFeature just calls wasm-feature-detect.
All the tests are in custom/wasm.json, where they have a readable name as the key, and the wasm-feature-detect name as the wfd-key value.

[queengooborg]

Thank you for working on this, @MendyBerger! This is looking quite wonderful so far!

There are a couple of things that we should do to ensure that the collector will still run in older browser versions:

• First, async/await syntax cannot be used, especially in harness.js -- luckily, we can just remove those keywords, as the collector is designed to handle promises!
• We should try to avoid adding the library's script directly to tests.ejs, and instead write a script to try and load the script, or set the wasmFeatureDetect variable to false if it couldn't be loaded.
  • On that note, in the testWasmFeature() function, there should be additional checks in place to make sure that wasmFeatureDetect is defined and is truthy, and that [feature] is defined in that variable
• We should also put the testWasmFeature() function below testCSSProperty(), especially as right now, it's defined right below the JSDoc for testCSSProperty()

(If you'd like, I'd be more than happy to continue the development on this and get it ready to merge and deploy!)

[MendyBerger]

If you could easily do those things, please do. Otherwise, I'll take another look when I have the time.
Either way, let me know.

[queengooborg]

I've just made some changes to get this all ready to deploy! I've just got one question for you in regards to formatting wasm.json, otherwise this looks great!

[queengooborg]

Do you think that we should just simplify this to be "bcd-key": "wfd-key"?

[MendyBerger]

No strong preference. I did it this way so that in the future, we can add more configuration fields, but that might not be necessary.

[queengooborg]

I figured that was the case, but I wasn't sure if you had any configuration options in mind -- I'll leave the format as-is just in case!

[MendyBerger]

@queengooborg how long should it take until these results show up in caniuse.com?

[queengooborg]

I can't say how long it would take for CanIUse to obtain them because it's a third party service, but for BCD, I'm hoping to get them added as soon as the new collector version is released. It may be a bit because I'm planning to increase category coverage and have a few other updates I wish to make, but once it's out I'll get a PR going to add this new category into BCD!