Increase Download Size or Change Modal for Selecting Download Area

[cgiovando]

Tested on https://export-staging.hotosm.org/en/v3/exports/ (staging)

The guided export creation process doesn't warn about the max download size (nodes or area) until the final "Create Export" button is clicked.

I would suggest increasing the export size to handle areas as large as a country (e.g. France) with at least one set of OSM features/tags. As an alternative, the warning on max export size should be provided earlier in the process.