Livestream support for amp-jwplayer

For amp-youtube, we have the option to include the channel details (`data-live-channelid`) for live stream videos. Will it be possible to add something like this for amp-jwplayer?

The option I'm aware of is to get the channel's JSON data and based on the status(active or not), fetch the player URL and plug it into the source URL for an iframe or video player. [Documentation](https://www.jwplayer.com/developers/web-player-demos/live-channels/). The issue with this is that the API will have to be hit occasionally on the client side to check if the live stream has started or not, and dynamically provide the source URL to the iframe/video player. I'm not aware of how(or if) this can be done with AMP. The other option is to do this on the server side. But then again there's the cache issue.

Start with the amp-jwplayer component and the linked JW Player live-channels documentation. Determine whether AMP can support live-channel status and source updates without client-side polling or cache problems. Done means a documented, technically agreed approach for livestream support, with any required implementation scope identified.

Written by the indexing model from the issue text.