Implement video data retrieval & saving

[leingenm]

Pull Request

Description

Introduced controller and service layer that handles data retrieval and saving into the database.

Videos can be imported by providing a CSV file or a list of video IDs.

Video data retrieval happens in batches and is handled using transactions. If a transaction fails neither video IDs nor video data is saved.

Implemented an endpoint allowing checking of what transactions have failed and which were successful.

Related Issue

Issue #32

Checklist

Please review and check all applicable items:

• I have tested my changes thoroughly
• My code follows the project's coding standards and guidelines
• I have added necessary documentation (if applicable)
• I have updated relevant tests (if applicable)
• I have reviewed my changes to ensure there are no unnecessary changes
• My pull request has a descriptive title and includes a detailed description of the changes

Additional Notes

• Updated collections in Postman
• Disabled Liquibase in tests. Created a separate Spring profile for testing and updated GH Actions step to use it when running tests in CI

Screenshots (if applicable)

[daverbk]

wow, it's so big