Deduplicate message templates when written by RenderedCompactJsonFormatter

[ngbrown]

When using RenderedCompactJsonFormatter, instead of outputting the message template (in @mt) and relying on the reading program to substitute in all the parameters, @m has the fully rendered text. The unique template hash is in @i.

The list of message templates on the right side of the app should de-duplicate among all the entries with the same @i (definition). Since the actual used template isn't available, just say something like "and xx similar".

When clicking on an entry on the right side, instead filter on @i or @EventId instead of @MessageTemplate.

That way the message template filter will work the same, and an application isn't strictly necessary to read a JSON written log file.