Allow autofill for plugin UIs

[buehlefs]

• document autofill message in asyncapi spec (see https://github.com/UST-QuAntiL/qhana-plugin-runner/blob/main/docs/asyncapi.json) Tracking issue: TODO
• implement autofill message in microfrontend.js in the plugin runner. Tracking issue: TODO
• implement autofill in UI
  • Add button to trigger autofill to plugin ui component
  • Implement autofill based on past plugin executions (this should also work for substeps with the same step id)