Add support for object output

Hey, great library!

I’m about to release a new <svg-icon> library where I recommend and show how to use this library.

In my library, we expect to get an object where the key is the icon name, and the value is the content:

{
  settings: 'svg...'
}

Currently, I expose a function helper that’ll make it work with your library:

import * as icons from '../assets/svg/my-icons.model';

SvgIconsModule.forRoot({
  icons: fromSvgProps(icons)
});

Do you think you can add this option as a built-in feature?

[NetanelBasal]

I added in the README a recommended flow with your library.

[NetanelBasal]

I also think the default delimiter should be camelCase. This is the standard.