Support FIPS for S3 Outposts

[trivikr]

Fixes: #3961
This PR will be made ready once #3962 is merged. Ready!

Testing

• Unit testing.
• Verified that URL is generated for S3 Outposts Control Plane.

Code

import AWS from "../aws-sdk-js/index.js"; // v2.1029.0

const region = "us-gov-west-1";
const useFipsEndpoint = true;
const AccountId = "123456789012";
const Bucket = `arn:aws-us-gov:s3-outposts:${region}:${AccountId}:outpost:outpost-name:bucket:bucket-name`;

const client = new AWS.S3Control({ region, useFipsEndpoint });
const req = client.getBucket({ AccountId, Bucket });
req.on('complete', function () {
  console.log({ hostname: req.httpRequest.endpoint.host });
});
req.send(function () {});

Output

{ hostname: 's3-outposts-fips.us-gov-west-1.amazonaws.com' }

Checklist

• npm run test passes
• changelog is added, npm run add-change