Add more options to configuration, make dates more consitent

[pawlowskim]

This PR adds new features like:

• add possibility to remove new lines sign from log texts. This is helpful if we want to have log to be exported to TXT and have it single-lined. It's configurable and turned off by default to not change how the plugin works
• add possibility to use milliseconds as timestamp string. Also configurable and turned off by default
• add empty fields to logs. It basically keeps text representation of the log with the same length if you split it by delimiters. Previously nulls were replaced with empty string. With this change it prints fe. "{}" instead of "". Also configurable and turned off by default.

Fixes:

• makes timestamps dates consistent. Previously it uses 2 instances of DateTime.now() for the same purpose.

It's up to date with master, and it's null safety.