Add programmable scenarios (.py extension), Scheduler, Plotter, Experiment Runner

[marvin-schl]

• Check if CustomScenario and BaseScenario are needed
• Proposal: Rename Scheduler to DataframeGenerator, ScenarioGenerator or something similar
• Call Generator directly in Scenario class if CustomScenario and BaseScenario are not needed
• Check if Plotter configuration is compatible with obsolete Logger configuration, if not make sure that backward compatibility is given

[marvin-schl]

LGTM