LinkedHttpContentReader Read Limits

[er1c]

This is a preview PR, but largely done - I might add another test or two, and then I need to go through the PR with a finer grain comb.

It adds additional support for maxLength limits in LinkedHttpContentReader and also introduces a MaxLengthStrategy parameter for controlling how the server should respond to the limit.

The added test includes an example usage:

      val res: Future[Response] = request.content.writeToFile(file, OneMB, LinkedHttpContentReader.MaxLengthStrategy.DiscardAndThrowException).map { _ =>
        Response.Ok(file.length.toString)
      }.recoverWith {
        case ex: LinkedHttpContentReader.MaxLengthException => Future.successful(Response.plain(Status.REQUEST_ENTITY_TOO_LARGE, "413 Request Entity Too Large"))
      }

This allow custom responses in case the upload is too large.

I also added support to the HttpClient and HttpServer for requesting and handle Expect: 100-continue patterns

Example:

> POST /webcat30/v1/services/htmlToPdf?fileName=bosch-1234.pdf HTTP/1.1
> Host: webservice-preprod.tecalliance.services
> User-Agent: curl/7.54.0
> Accept: */*
> X-API-Key: 2BeBXg64EewdEsApWYJpK76jWDY7w4L6ZNx1gkSPH3SpLkySKMnX
> Content-Type: text/html
> Content-Length: 522759
> Expect: 100-continue
>
< HTTP/1.1 100 Continue
} [16384 bytes data]
* We are completely uploaded and fine

The same exception LinkedHttpContentReader.MaxLengthException will get thrown early (before all of the content is read) if the Content-Length is part of an Expect: 100-continue request.