[FEATURE] Improve `apply_reference_operation` Compatibility with eGon Project Data

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Is your feature request related to a problem? Please describe.

The apply_reference_operation function does not work out of the box with home battery data from the eGon project. Additionally, there is no dedicated module within the EDisGo class to call this function directly. This makes it difficult to integrate the function seamlessly within workflows using eGon data.

Describe the solution you'd like

• Modify apply_reference_operation to support eGon project data without requiring extensive preprocessing or adjustments.
  • Set default values for battery efficiency if none are given
  • Introduced more concise error messages when e.g. generators were not loaded before running the `apply_reference_operation' or time series for generators and loads were not set
• Introduce a dedicated module or method within the edisgo class to allow direct calls to apply_reference_operation.

Describe alternatives you've considered

• Manually preprocessing the eGon data before using apply_reference_operation, but this adds complexity and reduces usability.