Performance telemetry

> **Note**
> This is a "meta" issue for tracking purposes since GitHub does not support special types of issues.

We can collect data about F# performance to have an overview of areas to optimize.

Some ideas:
- Intellisense (e.g. typed character to intellisense list time)
- Initial type-checking and re-checking
- Opened document to diagnostics time
- Opened document to highlighting time

@vzarytovskii, @T-Gro feel free to dump more here.
Meanwhile I will ask around how other teams do this.