Add ZIP-archive support

What does this MR do?

Adds loading and checking of CityGML ZIP-archives in CityDoctor.

Fixes report creation with Features added in version 3.16.0

Related issues

• #12 (closed)
• #104 (closed)

Checklist

• Commits squashed, following the message-template and containing changelog-trailers
• MR title and description are up to date, accurate, and descriptive.
• MR targeting the appropriate branch.
• Latest Merge Result pipeline is green.