…dance

The existing Invicti documentation only contained a one-line description 
and the default deduplication fields. This update expands it to include:

- Step-by-step export instructions for Invicti Enterprise
- Explanation of confirmed vs unconfirmed findings and how to 
  handle them in DefectDojo
- Native integration setup steps for Invicti Enterprise users
- Severity mapping table from Invicti to DefectDojo
- Recommended workflow for enterprise teams running Invicti 
  at scale across multiple applications
- Deduplication guidance for large scans