* 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