WIP: Is234/update py requirements

[pcrespov]

What do these changes do?

New workflow to avoid package compatibility issues:

• pins all python dependencies
• requirements/staging.txt with package versions and hashes
• compilation workflow: deps in setup.py -> pip-compile -> pip install or pip-sync
• configs pyup bot to check weekly for security vulnerabilities

Cleanup of requirements in the following hierarchical order:

• packages/servicelibs
• rest in packages (simcore-sdk, ...)
• storage
• webserver

Related issue number

connected to #234
closes #234

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• Runs in the swarm
• If you design a new module, add your user to .github/CODEOWNERS