PageParams TypeScript interface improvement on DataTable, TreeTable and DataView

[hstevanoski]

I'm submitting a ...

[ ] bug report
[X] feature request
[ ] support request

Current behavior
The DataTablePageParams interface used in the DataTable's handlePaginationChange method is currently defined as:

interface DataTablePageParams {
    first: number;
    rows: number;
}

but it's missing the page and pageCount properties.

Screenshot of the actual event object when logged in the console:

Expected behavior
The interface should include the aforementioned properties as well.