Nicer error page on configuration error

[timja]

What feature do you want to see added?

Currently when you reload the configuration you get:

On startup failure you get:

Big screenshot

This is inconsistent, both have a poor UX though.

The error should be visible to the user without having to view the logs.
There should not be a stacktrace by default but possibly it should be able to be made visible

Line numbers and file name should also be provided

Upstream changes

No response