Make the property names of the Serilog log property names of the enrichers configurable

[stijnmoreels]

Is your feature request related to a problem? Please describe.
Right now, we ust hard-coded Serilog log property names during the enrichment of the log events, and document them what they are. This may lead to inconsistent logs as certain naming conventions should maybe be inforced in a project.

Describe the solution you'd like
Make the property names configurable and use the current property name as the default one.