Create blogpost from Advanced debugging deck

Slides - https://docs.google.com/presentation/d/17HjGp4pQlNh2WIwKiTcUpDLIuOdkUcRmALFuoytQsjU/edit#slide=id.p Video - https://www.youtube.com/watch?v=B63jNjSVEbQ&feature=youtu.be

Create post for h5r from this content cc @paulirish

Proposed TOC:

• Productivity
  • Workspaces
  • Network request filtering
  • Asynchronous callstacks
  • JS framework blackboxing
  • Command Line API
  • Workers
• Performance
  • Layers
  • Memory allocation profiler
  • Layout invalidations
  • Flame chart
  • Profviz
  • Timeline flame chart
  • about:tracing
• Mobile
  • Screencast
  • Device mode
  • performance.memory
  • window.onerror
  • Timing