chore: remove is prefix from constructors

[carlos-menezes]

Example usage:

const view = alt.WebView.create({
  url: "http://resource/client/html/index.html",
  overlay: true // previously: `isOverlay: true`
});

const audio = alt.Audio.create({
  source: "https://www.myinstants.com/media/sounds/vine-boom.mp3",
  volume: 10,
  radio: true // previously: `isRadio: true`
})

Closes #192

[carlos-menezes]

[Yiin]

lgtm @xLuxy