Refactor fetch calls

[ChristianMurphy]

There is an increasing pattern of duplication in our fetch calls.

const response = await fetch(
  contextApiUrl + process.env.VUE_APP_BROWSABLE_PORTLETS_URI,
  options
);

if (!response.ok) {
  throw new Error(response.statusText);
}

const {portlets} = await response.json();

This code may be simplified, and we can gain some new features, like timeout, using a wrapper library like ky.