[OB3] Modify Dockerfiles to accept external files with .zip extension

[shadhini]

Purpose

OB3 Dockerfiles accept zip files given from the docker release pipeline as tar.gz files and try to extract them considering them to be tar.gz files. While extracting them (externally passed zip files) using tar command, an error occurs as they aren't properly converted tar.gz files and thus, OB3 docker builds fail.
This PR add necessary modifications to Dockerfiles so that they would accept zip files instead of tar.gz files.

Related Issues

#133

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