Fixes, add `probability` parameter for sparse metrics

• Add checks for meaningful starting parameters for some types of metrics
• Add probability for sparse metrics, when some points are missing
• Migrate to github.com/pelletier/go-toml/v2

Fix flags parsing

• --const, --counter and --random flags aren't additionally split by commas anymore

First working version

Merge pull request #1 from Felixoid/first-release

First release