Add telemetry for investigation of perf

[greazer]

first step is to brainstorm what to measure.

[rchiodo]

• Create environment time
• Jupyter launch time
• Jupyter connect time
• Jupyter hidden cell time
• Jupyter run cell to actual display time (cold start)
• Jupyter run cell time

[rchiodo]

Here's the total list @IanMatthewHuff and I came up with:

• Code lens acquisition time (this will be averaged over the entire session since it happens so often)
• DI ctor time
• Enumerate environments time
• Jupyter process launch time
• Jupyter find process to launch time
• Jupyter wait till idle time
• Jupyter silent/hidden cell time (our matplotlib theming and directory switching)
• Jupyter cell execution time
• Jupyter restart time
• Jupyter kernel interrupt time
• Run cell total perceived time (both first time and every time)
• Webview style update time
• Variable explorer fetch time
• Data Viewer web view startup time
• Data viewer data ready time
• Plot Viewer web view startup time