Download experiment results from DC

[FHardow]

Is your feature request related to a problem? Please describe. Thanks to @tstadel the deepset cloud sdk holds functionality to create and start an experiment run. We are currently missing the functionality to download the results as dataframe or as csv file. This ticket aims to add these two things as extra function to the DeepsetCloudExperiments class.

~- [x] function to download the csv file~ will be done by the functionality below

• [x] function to download the predictions ~per node~, should return ~a pandas dataframe~ a EvaluationResult object
• [x] tests

Describe the solution you'd like Add a function to fetch predictions and the experiment result dataframe from deepset cloud.

Additional context API endpoint definitions can be found here.

[tstadel]

@FHardow the second checked point should result in a proper EvaluationResult object being returned. This is just a container around the dataframes with additional functionality like calculate_metrics, etc.

[FHardow]

Okay will change it in the description, thanks for the comment :)

[FHardow]

Completed with https://github.com/deepset-ai/haystack/pull/2960