Tutorial Solution Uploader - TEST MODE

A small update on tutorial deployment script. The important highlight of this script is as follows:

• TEST_MODE is added as a flag in environment variable. If this flag is set, a random 4 digit string would be appended to the solution's name, to make it unique.
• Fixing each tutorial solution's display issue in the design studio:
  • House Price Prediction
  • Named Entity Recognition
  • Sentiment Analysis
  • Sudoku Solver
  • Training Pipeline (News Classifier)
• Restructuring the code, the code for model uploader class and pipeline uploader class are now in their own separate files. And both these inherit from parent solution uploader class.