Missing doc strings

[yangwenzhuo08]

Besides, the doc strings in each Config Class (the meaning of each algorithm parameter):

1. logai/analysis/clustering.py: "fit", "predict"
2. logai/algorithms/anomaly_detection_algo/arima.py: This file is empty, can be deleted.
3. logai/algorithms/anomaly_detection_algo/dbl.py: "fit"
4. logai/algorithms/anomaly_detection_algo/distribution_divergence.py: "fit", "predict"
5. logai/algorithms/anomaly_detection_algo/ets.py: "fit"
6. logai/algorithms/anomaly_detection_algo/one_class_svm.py: "fit", "predict"
7. logai/algorithms/anomaly_detection_algo/prophet.py: This file is empty, can be deleted.
8. logai/algorithms/nn_model/transformers.py: all
9. logai/algorithms/parsing_algo/ale.py: all
10. logai/algorithms/parsing_algo/drain.py: all
11. logai/algorithms/parsing_algo/iplom.py: all
12. logai/algorithms/information_extraction/feature_extractor.py: all
13. logai/algorithms/information_extraction/log_vectorizer.py: all
14. logai/algorithms/preprocess/partitioner.py: "group_sliding_window"
15. logai/algorithms/preprocess/preprocessor.py: all
16. Delete all .DS_Store

[amritasaha87]

Added documentations and raised PR on this https://github.com/salesforce/logai/pull/24

[qcheng-dev]

PR merged