Lin 673 lineapy.get for MLflow

[mingjerli]

Description

• Implement LineaArtifact.get_value() for artifacts that use MLflow backend.
• Implement LineaArtifact.get_metadata() for artifacts.
• Implement lineapy.api.delete to delete MLflow artifact record from lineapy db (not touching MLflow artifact side)
• Annotate statsmodel and xgboost and add to MLflow integration.
• Add RTD docs for MLflow integration

Fixes # (issue)

LIN-669, LIN-673, LIN-675, LIN-676, LIN-690

Type of change

Please delete options that are not relevant.

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

How Has This Been Tested?

• Adding LineaArtifact.get_value and LineaArtifact.get_metadata to existing test.
• For lineapy.delete, manually validate the artifact entry has been deleted from node_value, artifact and mlflow_artifact_storage tabels.

[yoonspark]

To add new docstrings into RTD's API reference page, please run:

cd docs && rm -rf build source/build source/_build source/autogen && SPHINX_APIDOC_OPTIONS=members sphinx-apidoc -d 2 -f -o ./source/autogen ../lineapy/ && make html

This will update docs in lineapy/docs/source/autogen/, which should be committed.