Simplify pagination

[luisherranz]

We don't have to use libraries.source.parse and libraries.source.stringify for next and previous page anymore, so we can simplify this code: https://github.com/chakra-ui/frontity-chakra-ui-theme/blob/master/packages/frontity-chakra-theme/src/components/archive/pagination.js#L63-L78

const { totalPages } = state.source.get(state.router.link);
const { path, page, query } = libraries.source.parse(state.router.link);

const isThereNextPage = page > 1;
const isTherePreviousPage = page < totalPages;

const nextPageLink = libraries.source.stringify({
  path,
  page: page + 1,
  query,
});

const prevPageLink = libraries.source.stringify({
  path,
  page: page - 1,
  query,
});

And just use the next and previous we get from data:

const { totalPages, route, page, next, previous } = state.source.get(
  state.router.link
);

Please note that path has been renamed and is now route.

Docs: https://docs.frontity.org/api-reference-1/wordpress-source#state