Possibility to add top-level property and not within "Properties"

[Kiechlus]

Right now, the logs look as in the following screenshot.

• All properties by the application are within the "Properties" section
• Is it somehow possible to put certain properties on top-level
• We would need that for the CorrelationId

[gh123man]

You can now do this by supplying a custom ITextFormatter with https://github.com/DataDog/serilog-sinks-datadog-logs/pull/86 in v0.4.0. There is an example in the readme.