Refactor extension config and random data generation

[na--]

Look at this commit by commit. The summary is:

• I added support for an object-based config, so we can add additional configuration options without exploding the number of loki.Config() positional parameters
• Removed the artificial restriction for creating a Config in the init context
• Inlined a partial copy of the github.com/chaudum/flog dependency and refactored all pseudo-random data generation to be deterministic, controlled by the initial randSeed value in every Config.

⚠️ This PR also fixes a major bug where pushParameterized() didn't send the specified amount of data, it only sent 1/numStreams! See 243abf4

[vlad-diachenko]

LGTM