[Feature Request] Add activity debugger sample

[lorensr]

Is your feature request related to a problem? Please describe.

Couple users have asked how to do activity debugging.

Describe the solution you'd like

Sample with a launch.json and a README that tells you what steps to do.

https://code.visualstudio.com/docs/editor/debugging

with something like:

"program": "${workspaceFolder}/lib/worker.js"

but make sure it works with breakpoints in TS file