Consolidate confidence score handling

[behas]

Currently, confidence scores are duplicated: in confidence.csv and tagstore_schema.sql

Proposed solution: enhance tagpack-tool as follows

• tagpack-tool confidence show -> list confidence scores
• tagpack-tool confidence ingest -> ingest confidence scores into DB (-f to force overwrite)
• remove confidence INSERT statements from tagstore_schema.sql

[mdragaschnig]

depends on #29

[cybersec-code]

Now the confidence parameter allows to show or ingest confidence scores