Making requests with timeout

Specifying a timeout when making a web request seems like a core feature, otherwise your code is at the whim of whatever you're communicating with.

Usually I'd pass a `AbortSignal.timeout(time)` in the fetch options.

Another solution would be to race the promise with setTimeout. Doesn't look like the promises package exposed race functionality though.

Possibly linked with #4.. depending on the approach

Related:
https://github.com/gleam-lang/javascript/issues/11
https://github.com/gleam-lang/javascript/issues/10

Start by reading the fetch options and promises APIs described in the issue, then review #4 and the two linked JavaScript issues for the intended direction. Done means requests can honor a caller-specified timeout with documented behavior and coverage for the chosen approach.

Written by the indexing model from the issue text.