REANA-Workflow-Controller 0.5.0

• Adds support to create interactive sessions so the workspace can be explored and modified through a Jupyter notebook.
• Creates workflow engine instances on demand for each user and makes CVMFS available inside of them.
• Adds new endpoint to compare two workflows. The output is a git like diff which can be configured to show differences at metadata level, workspace level or both.
• Adds new endpoint to delete workflows including the stopped ones.
• Adds new endpoints to delete and move files within the workspace. The deletion can be also done recursively with a wildcard.
• Adds new endpoint which returns workflow parameters.
• Adds new endpoint to query the disk usage of a given workspace.
• Makes docker image slimmer by using python:3.6-slim.
• Centralises log level and log format configuration.