Open Peer Review: Enhance review UX of nested metadata properties

Description of the issue

We want to make it easier to navigate the metadata properties especially when working on the deeply nested properties. This helps alot when working with extensive metadata and is still good for minimal metadata.

As it is currently we force the user to click twice to get to the information they want to review. Below you see a snippet form the enhanced peer review UI. :

Ideas of solution

Remove the accordion functionality from "Timeseries 1". Just how it as a headline for that first timeseries element in the list. Keep the accordion for "Timeseries" level.

Implement the same fix for "Sources" and "Licenses" properties.

Workflow checklist

• I am aware of the workflow in
  CONTRIBUTING.md