Add option to include/exclude any default fields #36

[peitschie]

• Modifies existing IncludeSeverity option to disable field as well
• Add release note and uprev package

Addresses #36

[peitschie]

Personally, my preference is https://github.com/pada57/serilog-sinks-influxdb/pull/38 as a nice way to turn off all the default fields.

This one is a bit too fiddly in my opinion, and I don't like the need to either change the behaviour of IncludeSeverity or add an additional IncludeSeverityField (it's also likely missing a IncludeMessage option as well).

If you prefer this kind of approach though, I'm happy to extend it with the above tweaks to make not change any existing in-field behaviours and be purely opt-in.

[peitschie]

Actually, the more I fiddle with this, the less I like it. Closing this out in preference to my second PR.