Have a page that supports a range of messages

This is based on a question by Jacky on the IndieWeb Chat.

You can currently look at a channel in the logs or a single message in the logs, but it would be great to be able to link to a range of messages in the logs.

currently `/channel/date/timestamp` links to a single message.

so potentially we could turn `/channel/date/startTimestamp/endTimestamp` or `/channel/date/startTimestamp-endTimestamp` into an h-feed of messages between those two points in time

Start by tracing the existing /channel/date/timestamp route and the log page that displays a single message. Determine how a start and end timestamp should be parsed, then make the range URL produce an h-feed containing messages between those points. Done means both proposed range URL forms have defined behavior and link to the expected message range.

Written by the indexing model from the issue text.