Add an API to create a flame graph from profiling data. Also adds a demo scene showcasing the functionality that generates some profiling data by measuring dummy function calls and rendering a flame graph for the dummy data (see video for the result).
Not that the functionality is not yet exposed user-facing in the GUI itself, but only as API and demo scene, therefore [ci no changelog needed]
https://user-images.githubusercontent.com/1428930/155118977-ecac0628-777c-48bd-9aa7-30ee6aef1976.mp4
# Important Notes
* Change from the initial design: labels are shown on the flame graph instead of as a tooltip. This is because tooltips are currently only implemented in the graph editor and would require some additional refactoring (probably taking the better part of a day).
* re-instated the behaviour that logs are shown in the JS console if development mode is active.
