Propose/Design the way of referencing/using VS OTel

[JanKrivanek]

Motivation

VS OTel collector and extensions require dependencies that are currently only VS specific (Microsoft.VisualStudio.OpenTelemetry.ClientExtensions, Microsoft.VisualStudio.OpenTelemetry.Collector). We need to start collector ourselves if we want to collect data from standalone process (msbuild.exe run).

Additionaly - We currently produce the MSBuild bits - including the msbuild.exe - from our GH repo, that is expected to be source-buildable.
The requirement technicaly applies only to the core version.
Also - we want runnable bootstrap - in order not to break our testing infra

Goal

Propose/Design the way of referencing/mounting VS OTel extensions and collector. The proposal should be approved by msbuild team + product construction team.

[JanKrivanek]

Inspiration provided by @baronfel: https://github.com/baronfel/otel-startup-hook