Apply classes to an element.

1. Default Angular bindings ([class.x] and [ngClass]) do not allow to bind dynamic class-names based on boolean/string values.

2. @HostBinding can not provide ngClass functionality, if we want to bind classes from component.

$ ng add @novyk/sx-class

<div [sxClass]="{color: 'red', active: true, primary: false}">
<!--<div class="color-red active">-->

constructor(private sxClass: SxClass) {}
...
this.sxClass.apply({color: 'red', active: true, primary: false});

Adds to element: class="color-red active"