Token metadata http requests rejected on development

[tuliomir]

In the development environment, whenever the Desktop Wallet tries to fetch token metadata it receives a CORS error from the Wallet Service.

Access to XMLHttpRequest at 'https://explorer-service.hathor.network/metadata/dag?id=00' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

This makes it so that the behavior of the wallet in development is different from that of the production version.

We should have an alternative for interacting with the explorer service without any errors, even if limited to the testnet network.

Note

Developments on #488 indicate that the metadata errors may be happening in production as well, but they are not finding a way to be displayed to the user.