Default logger with full output

[Thomasillo]

It would be nice to have a default formatter (Inheriting from JsonFormatter) which includes all possible logRecord fields in the formatted json without the need to specify them explicitly..
This way you don't have to specify all field names manually in your logging configuration.
Which is also not advantageous because you have two sources of truth then (your configuration file and pythonjsonlogger resp the stdlib logging module.).