Collect metrics on OpossumUI usage

[benedikt-richter]

Context
It is difficult to understand which features are used by users of the OpossumUI. Therefore, it is difficult to answer questions, like: How is the adaption of the Attribution Wizzard?

Proposal
Save metrics on the usage of features in the OpossumUI output file.

• The number of usages of relevant features should be stored in the output file (e.g. how many times was the Attribution Wizard opened or the save button in the Attribution Wizard used?)
• The data could be saved in the output.json under an additional top level key usageMetrics. It might have the structure:
  • usageMetrics: {AttributionWizard: {number_of_opening: 10, number_of_created_attributions: 5}}