☠️ WIP ☠️ Show traces in a call hierarchy

[andytill]

Show the traces in the call hierarchy instead of a flat table.

Intended benefits:

• Order of calls and when they return should be easier to read.
• Origin of exceptions should be easier to read. In a flat list all the functions in a call stack will be highlighted red and it is not clear where the exception came from without some digging.

TODO:

• Toggle between flat and hierarchy modes. Flat view is still useful to see call order between processes.
• Fix trace filtering, which is not currently working.
• Show call duration used just in the function call, not in functions it calls.
• Highlight rows that are waiting results or have errors