Increment Style size for each component in angular that use theme variables

### Issue type

**I'm submitting a ...** (check one with "x")

* [ ] bug report
* [x ] feature request

### Issue description
When a component has a customize theme variables the size of bundle increase big size

**Steps to reproduce:**

Create a componente that use a theme variable. The size increase about 300kb for each component

**Related code:**

```
@import '../../../themes';

:host {
background: nb-theme(background-basic-color-1);
}
```