[Component] Number input

[flore2003]

We need to extract our number input and expose it as part of this library. We also need to create tests for the component, before it can be included in the library.

[ditoglez]

In order for the component to work in the library I had to provide the DecimalPipe in component's providers. After that, it seems to work correctly with template-driven and reactive forms.

[ditoglez]

Updated the component to use formatNumber instead of DecimalPipe

[ditoglez]

@flore2003, @erzaehlsalex, I think this should be provided as an NgModule in case someone would like to use it standalone. What do you think guys?

[flore2003]

Yes, I think that is a good idea, let's do it like ng-bootstrap does it: One NgModule per Component/Feature and then one top-level NgModule for the whole library as a convenience module that imports all other modules.