WAITING FOR OTTO - Add Time Filter and Multiple Program Selection for Application Exports + Add Excel Import/Export Support

Description

• Add an Academic Period Filter for Application Exports (also FlexDelft)
• Add support for selecting multiple programs when exporting applications (also FlexDelft)
• Add Support for Excel Imports/Exports - (all imports/exports)

Related Issues

• Resolves #206 (closed)
• Resolves #175
• Resolves #190

Checklist

• I have added a changelog entry to reflect the significant changes I made.