AWS Elemental Link and MediaLive add KLV metadata support

You can now use [AWS Elemental Link](https://aws.amazon.com/medialive/features/link/) and [AWS Elemental MediaLive](https://aws.amazon.com/medialive/) to ingest and deliver KLV metadata from a MediaLive channel. KLV (key length value) metadata is suitable in many diverse use cases since you can define the keys and values to suit your content and application. Carrying this metadata from source to delivery enables the creation of enhanced viewing experiences with the combination of rich data streams with video and audio. For more information on how to enable this feature, visit the [MediaLive](https://docs.aws.amazon.com/medialive/latest/ug/what-is.html) and [Link device](https://docs.aws.amazon.com/medialive/latest/ug/feature-elink.html) documentation. KLV metadata in MediaLive is available at no additional cost. [AWS Elemental MediaLive](https://aws.amazon.com/medialive/) is a broadcast-grade live video processing service. It lets you create high-quality live video streams for delivery to broadcast televisions and internet-connected multiscreen devices, like connected TVs, tablets, smartphones, and set-top boxes. The MediaLive service functions independently or as part of [AWS Media Services](https://aws.amazon.com/media-services/), a family of services that form the foundation of cloud-based workflows and offer you the capabilities you need to transport, create, package, monetize, and deliver video. Visit the [AWS region table](https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services/) for a full list of AWS Regions where AWS Elemental MediaLive is available.