Revisit the multiple download URLs in conandata.yml

conandata.yml can contain multiple download URLs for the same version, as seen here https://github.com/conan-io/conan-center-index/blob/02ff9d0d653fa0ca9c2cba9ce1c46bef0e79f176/recipes/boost/all/conandata.yml.
Currently, `ConanDataHandler` considers the first URL as the download_url and discards the rest. We should revisit this at a later stage to collect these URLs as well, as they could provide additional information about the package.