Pluggable stack trace formatting

[dmlloyd]

This is a potential approach to allow a pluggable stack trace formatter.

Note a couple of important points:

• Service loader cannot be used at this early stage of bootstrap. It doesn't overtly fail with an exception, but certain things fail to initialize in the right order randomly resulting in sporadic and hard-to debug unit test failures. Idea: introduce a private logmanager-safe service loader, if we want more things to be pluggable?
• There is only one global stack trace formatter. It might be possible to allow different stack trace formatters per each PatternFormatter, but this would require extra logic and configuration which would need to be thought out somehow.
• This kind of functionality would be necessary to support something like provide source file context for exception message quarkusio/quarkus#37002

[dmlloyd]

I want to see how this could interplay with a general formatting API. I'll keep it here for reference for now though.