Check uploaded files

### Vision

As a user, I would like to be informed that my file does not have the expected content directly after uploading it. At the moment, I configure the complete experiment just to get the information that something went wrong during the experiment.

### Solution

We could provide different SHACL shapes for experiment types which check whether the uploaded file contains the expected data.

No files, tests, or entry points are named. Start by locating the upload handling and experiment-type definitions, then determine how SHACL shapes would validate expected data immediately after upload; done requires agreed shapes and a clear validation result before experiment configuration.

Written by the indexing model from the issue text.