mat-icon: mat-icon doesn't fully support outlined, rounded, sharp and two tone

#### Feature Description

Current implementation of `mat-icon` is incomplete, we can only use icons of filled style. We need a way to easily use outlined, rounded, sharp and two tone variant of material icons, something looking like:
```html

```

#### Use Case

Currently, using outlined, rounded, sharp and two tone variant of material icons is really inconvenient. We need to use some workaround, like
```javascript
@import url("https://fonts.googleapis.com/icon?family=Material+Icons|Material+Icons+Outlined");
```
```html
home
```
which is discussed in https://github.com/angular/components/issues/11544, and this method does not make use of `mat-icon`, as it's a general web solution to use oulined icons.

Comienza revisando la implementación actual de mat-icon y la discusión relacionada en el issue 11544. Confirma cómo se seleccionan actualmente los iconos filled y, a continuación, define cómo deben exponerse mediante mat-icon las variantes outlined, rounded, sharp y two-tone; se considerará completado cuando cada variante solicitada funcione sin el workaround de CSS documentado.

Escrito por el modelo de indexación a partir del texto del issue.