Release: update release artifacts

[bzz]

Right now, Gemini has 3 use cases:

1. local, for developer on pre-configured environment, using shell scripts
2. local, for a first-time user, Making gemini easier to run #84 (comment)
3. k8s \w Apache Spark cluster, Dockerfiles: Gemini \w Spark, Feature Extractors

Current release artifacts are only .tar file for 1 and a Docker file.

This issue is about changing the release process to accommodate recent changes on file-level similarity so:

• add .sh for starting a feature extractor process on local machine
• in ./report, check if Python is available
• make sure Dockerfile for FE re-uses the shell scripts (as much as possible)
• add publishing Docker container for FE to the release process
  (this will enable testing Gemini on 3rd use-case)

this way, a new release should accommodate all 1 and 3 case from above.