Add tabs adapter for TabLayout

Nadie ha tomado este issue todavía.

`TabLayout` creates the tabs in an opaque, non-extensible way and there is no way to provide a custom view at creation time, you have to hack around it with an observer set on the content source (e.g., a `ViewPager` adapter) and then use `setCustomView()` on each tab, after they're created.

Besides, the way tabs' views are created prevents libraries such as [Calligraphy](https://github.com/chrisjenx/Calligraphy/) from correctly applying a typeface to the default tab views, because the `TextAppearance` is applied only after inflating the view, and there's no way to access the tabs pool nor any hook into the creation of new tabs.

### Suggested changes

Have a mechanism to create and bind the tabs' views, similar to list adapters, that have a `createTabView()` and a `bindTabView()` methods. The default implementation would simply retain the current behaviour; users could extend the default implementation to tweak the tabs' appearance (e.g., `CalligraphyUtils.applyFontToTextView(tabTextView, typeface);`) or to inflate their custom tab views without the waste of always inflating the default layout anyways.

Comienza en la ruta de creación de pestañas descrita en el issue, incluida su interacción con un adaptador de ViewPager. Define cómo createTabView() y bindTabView() conservarían el comportamiento predeterminado y permitirían vistas personalizadas y la aplicación de typeface; se considera terminado cuando los llamadores pueden personalizar la creación sin inspeccionar la fuente de contenido ni inflar un layout predeterminado no utilizado.

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