Formatting library

[bettinaheim]

The currently used formatting library generates a couple of warnings that have been disabled by PR #158 by introducing an additional header file that disables these warnings for the include. The warnings may go away with an update to gcc 12.2. This issue is to track coming back to that header file and see if we can eliminate it - either by a compiler update, or by using a different formatting library.

[schweitzpgi]

In somewhat recent work to port to a modern version of LLVM, I upgraded fmt to a newer version to get rid of some compiler errors, etc. It's not entirely clear we can upgrade that way and there were recent discussions about making fmt "private" so as to avoid collisions with other users of the same library but newer versions.

I think we should just use the latest and greatest ASAP.

[schweitzpgi]

#3014

[aminx-hue]

Requires more work based on this comment 3014