Add deploy step for travis

[waldemar-becker]

Let travis do the standard way of packaging for us.

• Add pre-deploy tasks to pipeline
• Adjust Makefile help
• Get rid of filename template for simplicity

How to release a new package from now on:

make release

This creates a git tag on the repo, which triggers travis ci. Travis will then upload a package to official pypi with twine under the hood.