feat(api): image building process improvement

[naufalandika]

Context

This PR contains improvement for pyfunc-ensembler-service / pyfunc-ensembler-job image building process. This improvement removes the need of supporting specific python versions and use the python version specified in user dependency instead, similar on how merlin builds pyfunc-server and batch-predictor images.

Changes in this PR includes improvement for the imagebuilder, pyfunc-ensembler-service / pyfunc-ensembler-job package, and little bit of sdk.

imagebuilder

• Only use 1 base image for every python version used by the users.
• Inject pyfunc-ensembler-service / pyfunc-ensembler-job dependency to user's conda.yaml.
• Hash user conda.yaml to prevent the URL value of conda.yaml that has the same content to change and invalidating docker layer cache.

pyfunc-ensembler-service / pyfunc-ensembler-job package

• Add new Makefile rule to build and publish the package to pypi
• Add new github workflow to publish the package to pypi everytime sdk workflow is run successfully. pyfunc-ensembler-service / pyfunc-ensembler-job share the same version with turing-sdk package, but both of these package requires latest turing-sdk version, so we need to run the workflow only after sdk workflow completed.

sdk

• Change the trigger to sdk workflow to python/* tag push instead of sdk/* tag push. python/* tag and version will be used by turing-sdk, pyfunc-ensembler-service and pyfunc-ensembler-job packages.

Main Modifications

imagebuilder/imagebuilder.go:

• use 1 config for --build-arg=BASE_IMAGE=%s value
• hash user's conda.yaml

engines/pyfunc-ensembler-*/Makefile:

• add rule to build and publish pyfunc-ensembler-* package

engines/pyfunc-ensembler-*/app.Dockerfile:

• injects turing-pyfunc-ensembler-* to user's dependency

.github/workflows/*

• add publishing python/* tag as sdk workflow triggers
• run pyfunc-ensembler-* workflow after sdk workflow is run successfully