[Feature Request] Separate sorting for replies

[ggtylerr]

Checklist

• I am running the latest version. Installing Isso from GitHub from the master branch does not fix my issue
• I have checked the troubleshooting guide
• I have searched the open issues, but my issue has not already been reported

What is not working?

When using the new sorting system introduced in #1005, replies are sorted the exact same as regular comments. If comments are sorted by newest first, the replies to said comments will also be sorted as such. This can potentially confuse the reader, as the reading order for threads is usually always oldest first. Here's an example of what it looks like now:

Note how the thread starts with the oldest post (the OP), then immediately after that, the newest post (the reply.)

How can one reproduce this issue?

On the client-side configuration, set data-isso-sorting to newest. (This is possibly also visible in upvotes too, but haven't tested yet.) Then, post a comment, and reply to it at least twice.

[ix5]

My personal preference would also be to list child comments chronologically (oldest first), that's how it is done on most platforms I know which only allow for 1 level of nesting.