Make "ts" and "level" values optional

[AntonPetrov83]

Hi!

In my case I use the Serilog.Sinks.Grafana.Loki sink to send logs to Grafana Loki.

This sink uses a Loki API to send records and it sends timestamps as a standalone value according to the API specification. Duplicating timestamps in logs with ts is useless and makes logs bigger.

I suggest making ts and level values optional through configuration. I can make a PR for that if you wish.

[eiximenis]

Hi @AntonPetrov83!
Sorry for long time to answer.

I feel this is a great idea, feel free to submit a PR if you still are interested in having this. If not, just let me know to add this feature anyway in a near future :)

[AntonPetrov83]

Hi @eiximenis!
Honestly I switched to JSON formatter for Loki it turned out to be more useful in my case.
Thank you for openness and good luck!