Add additional dependencies for ModelTrainer

**Describe the feature you'd like**
When migrating from sagemaker v2 to v3, the [Estimator](https://sagemaker.readthedocs.io/en/v2.256.0/api/training/estimators.html?highlight=tensorboardoutputconfig#sagemaker.estimator.Estimator) can be replaced by ModelTrainer. However, the ~~`tensorboard_output_config`and~~ `dependencies` parameters in Estimator has no equivalent in the ModelTrainer. This functionality would be useful to have in ModelTrainer to maintain feature parity with the v2 Estimator.

**How would this feature be used? Please describe.**
* Allows the import of additional source files and dependencies into the model training container.
~~* Allows debugging visualization using TensorBoard, with customization on the location in Amazon S3 to store the output, as well as the local path in the container.~~ (addressed by [ModelTrainer.with_tensorboard_output_config](https://sagemaker.readthedocs.io/en/v2.253.1/api/training/model_trainer.html#sagemaker.modules.train.model_trainer.ModelTrainer.with_tensorboard_output_config))

**Describe alternatives you've considered**
None

**Additional context**
None

Beginnen Sie am ModelTrainer-Einstiegspunkt und vergleichen Sie dessen Handhabung mit dem Parameter `dependencies` des v2 Estimator. Verfolgen Sie, wie zusätzliche Quelldateien und Abhängigkeiten in den Trainingscontainer gelangen, und überprüfen Sie anschließend, dass ModelTrainer die angeforderten Imports unterstützt und das dokumentierte Trainingsverhalten beibehält.

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