message: Convert to async function + ts syntax
diff: @@ -234,25 +234,22 @@ async function getFileContents(path: string, app: string, username: string | und
  zoneFileLookupURL: string | undefined,
  forceText: boolean,
  caller?: UserSession): Promise<string | ArrayBuffer | null> {
  - return Promise.resolve()
  - .then(() => {
  - const opts = { app, username, zoneFileLookupURL }
  - return getFileUrl(path, opts, caller)
  - })
  - .then(readUrl => fetchPrivate(readUrl))
  - .then<string | ArrayBuffer | null>((response) => {
  + await Promise.resolve();
  + const opts = { app, username, zoneFileLookupURL };
  + const readUrl = await getFileUrl(path, opts, caller);
  + const response = await fetchPrivate(readUrl);
  if (!response.ok) {
  - throw await getBlockstackErrorFromResponse(response, `getFile ${path} failed.`)
  + throw await getBlockstackErrorFromResponse(response, `getFile ${path} failed.`);
  }
  - const contentType = response.headers.get('Content-Type')
  + const contentType = response.headers.get('Content-Type');
  if (forceText || contentType === null
  || contentType.startsWith('text')
  || contentType === 'application/json') {
  - return response.text()
  - } else {
  - return response.arrayBuffer()
  + return response.text();
  + }
  + else {
  + return response.arrayBuffer();
  }
  - })
  }
  /* Handle fetching an unencrypted file, its associated signature
  