Provide script to import git log as csv

[JohT]

🚀 Git log data ingest

• Provide script to import git log as csv. With this script it is now possible to import git log data into the Graph and use it along side with other data to get even more insights into your code.
• Integrate git log import into analysis preparation
• Provide options for importing git log data. Git log import will be skipped when there is no source directory content. Even if there is a source directory (e.g. for Typescript analysis), then it is still possible to switch off git log import or reduce its footprint by using an aggregated (monthly grouped) variation.

⚙️ Optimization

• Remove workaround for reverted schema change.
• Reduce log noise by summarizing unused query results
• Fix minor typos