Lazy load CSS/Styles for components

### Issue type
* [ x] Question

### Description
I have the following lines in the style.scss which increases the size of stylesheet in bundle significantly.
```
@import '~@nebular/theme/styles/globals';
@import '~@nebular/theme/styles/theming';
@import '~@nebular/theme/styles/themes/default';
```

I checked the file and found that styles are imported for all the components whether they are used or not. Is it possible to load only the styles needed/ or lazy load styles?