Add external storage for test data

Description

• Upload (big) test data to SWITCHDrive
• Share with the link
• Place link as a protected (secret) variable
• Download test data in the CI

Related Issue

Closes #82 (closed)

How Has This Been Tested?

Tested in CI

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.