Add @Input() for total source count to allow server-side pagination

**Feature request:**

The pagination of this component is so beautiful.
The data I'm receiving from the server is `{data: Array(10), count: 93}` for instance

I wish the innate pagination component had the option to receive the count parameter to allow the same paging calculation (`Math.ceil ( arrayLength / perPage)`)

And then use the paging event output to fetch new data accordingly.

I would really not mind and be happy to do it myself if you would like, following any of your contribution guidelines