Implement data aggregation

[vitonsky]

Let user to request languages list where every language contains whole information about its usage per country and countries list.

Also it would be nice to have data filter for such query, to let user filter out data by usage and countries

[vitonsky]

As result user could fetch data with requests like

getLanguages({
  speakers: { min: 30_000_000, max: 300_000_000 },
  countries: {
   exclude: ['US', 'PL'],
  },
  sort: { by: 'countries', order: 'desc' },
})