This updates ESLint and our shared eslint-config-openlayers to use Prettier. Most formatting changes were automatically applied with this:
npm run lint -- --fix
A few manual changes were required:
* In `examples/offscreen-canvas.js`, the `//eslint-disable-line` comment needed to be moved to the appropriate line to disable the error about the `'worker-loader!./offscreen-canvas.worker.js'` import.
* In `examples/webpack/exapmle-builder.js`, spaces could not be added after a couple `function`s for some reason. While editing this, I reworked `ExampleBuilder` to be a class.
* In `src/ol/format/WMSGetFeatureInfo.js`, the `// @ts-ignore` comment needed to be moved down one line so it applied to the `parsersNS` argument.
This commit allows setting a z-index property on the layers and uses
it in the canvas, WEBGL and DOM map renderers for ordering the layers
before rendering.
Default z-index is 0 for managed layers and 1000 for unmanaged ones.
It allows always on bottom, always on top and more complex layer layouts.