debug/trace API finalisation and stabilisation

[canepat]

We're putting very focused effort in stabilising our implementation of debug and trace API endpoints.

This is the main tracking issue. Individual issues are listed below:

• [x] #2111
• [x] #2153
• [x] #2167
• [x] #2172
• [x] #2184
• [x] #2187
• [ ] #2036
• [x] #2050
• [x] #1652
• [x] #1801
• [x] #1802
• [ ] #1355