Support streamifyResponse

[willfarrell]

Closes #1038

• middy supports streamifyResponse with ReadableStream body
• middy supports streamifyResponse without ReadableStream body (needed?)
• Add new docs page
• http-content-encoding support ReadableStream body
• Update http-content-encoding docs
• real lambda testing

Test

Using Function URL, arm, nodejs18.x, esm

import middy from '@middy/core'
export const handler = middy({ streamifyResponse: true })
  .handler(() => {
    return {
      statusCode: ***,
      headers: {
        'Content-Type': 'text/plain',
        'X-Custom-Header': 'Example-Custom-Header'
      },
      body: ***
    }
  })