Federation timeout option

[istrau2]

Executing:
await StellarSdk.StellarTomlResolver.resolve(uri.host()); can cause an application to get stuck for a long time waiting for a response, especially if it is running on a server (and not in a browser).

Requesting:
An option for timeout in seconds after which the request times out no matter what.

[robertDurst]

Hey @istrau2 looking into this.

For reference, here is an example that causes this lag: xggtoken.com

[robertDurst]

@istrau2 made a PR, simple change. If you have a chance, would you mind giving it a look? I imagine this may help Stellarport verify assets ;)