mozjs: 17.0.0 - Mozilla's JavaScript engine

It's a new kind of release of SpiderMonkey: without any dependencies (were cmake and nspr), with fixed js-config. Makable, finally.

Mostly useful for testing JS code agains Mozillas version of JS.

Why named `mozjs` not `spidermonkey`? Because they name it this way: `mozjs` the package, `libmozjs-17.0` the library, and `js17` the runtime. The JaegerMonkey is inside, not SpiderMonkey.