add isolate_from_data and train_from_data, with refactor entrypoint (tekton prerequisite)

[sunya-ch]

This PR is a prerequisite for leveraging Tekton pipeline (#194) including:

significant changes:

• refactor cmd (entrypoint) code by separating cmd_plot.py and cmd_util.py for sub functions
• add data-path, abs-pipeline-name parameters to specify any data path by argument and to separate pipeline for isolation and output pipeline, respectively
• add isolate_from_data and train_from_data command to separate run isolator and trainer process out of the pipeline based on preprocessed dataframe. train_from_data introduces a new parameter trainers.
• allow to create a new data folder if not exist for query command
• add missing update_thirdparty_metrics call in train command
• auto fill default_trainers if abs_trainers/dyn_trainers is "default"

minor changes:

• round MAE, MAPE to 2 digits
• return -1 if cannot compute MAPE value

documentation changes:

• remove outdated command in cmd/README.md
• add description to each command function

Signed-off-by: Sunyanan Choochotkaew [email protected]

[rootfs]

this is a quite significant change, would appreciate if the doc can be added later.