SAR tests & small refactoring

Type of change

• [] Bug Fix
• Feature
• Tests

Does this introduce a change in the core logic?

• [No]

Does this introduce a change in the cloud provider implementation, and if so which cloud?

• AWS
• Azure
• GCP
• IBM

Does this introduce a change that must be documented in the README.md file?

• [No]

Updates description?

Describe your code changes in detail for reviewers (links on Gitlab issues, etc.)

• small file structure refactoring (common_crud.py was split into multiple files by endpoint)
• added tests for SamplesAnalysesReport
• added xfail mark to the test_get_non_existent_version_of_the_record (reason="issues/67")