Redesign the HTML renderer of Exceptions

[TimWolla]

With the introduction of middlewares the stack trace contains 2 frames per middleware that are identical for every request, clocking in at 19 stack frames for a simple request as of now.

This large block of text makes it hard to scan the stack trace for important information, especially since the middlewares take up the bulk of the space and are not that interesting.

The HTML renderer should be redesigned to make it easier to extract the important information.