* SDK - Moved the _container_builder from kfp.compiler to kfp.containers
This only moves the files. The imports remain the same for now.
* Simplified the imports.
* avoid istio injector in the container builder
* find the correct namespace
* configure default ns to kubeflow if out of cluster; fix unit tests
* container build default gcs bucket
* resolve comments
* code refactor; add create_bucket_if_not_exist in containerbuilder
* support load kube config and output error, good for ai platform notebooks/local notebooks
* remove create_bucket_if_not_exist param
* refactor component build code
* remove unnecessary import
* minor changes
* fix unit tests
* separate the container build from the component build; add support for directories in the containerbuilder
* minor fixes
* fix unit test
* fix tarball error
* revert changes
* unit test fix
* minor fix
* addressing comments
* removing the check_gcs_path function
* move namespace to the contructor of containerbuilder
* fix bugs
Alexey Volkov
Ning