fix(signature-v4): add hoistable headers config

[kuhe]

allows additive configuration over header hoisting with hoistableHeaders, where previously users could only configure the unhoistableHeaders.

For example, with S3, it was either incorrectly deduced or limited by S3 feature availability at the time that SSE headers were considered unhoistable. For backwards compatibility we will still default them to unhoisted, but as of today my testing shows this not to be true.

This change enables the following use case:

const params = {
  Key: "...",
  Bucket: "...",
  ServerSideEncryption: "aws:kms",
  SSEKMSKeyId: "arn:aws:kms:us-west-2:0000:key/abcd-1234-abcd",
};
const s3Client = new S3Client();
const command = new PutObjectCommand(params);

const preSignedUrl =
  (await getSignedUrl(s3Client, command, {
    hoistableHeaders: new Set(["x-amz-server-side-encryption", "x-amz-server-side-encryption-aws-kms-key-id"]),
  }));

context: aws/aws-sdk-js-v3#1701