Use C# build automation tool

[pellared]

Why

Currently, the build pipeline is tightly coupled to Azure Pipelines which makes it very hard to run the build in the local environment.

What

Migrate the build pipeline to use https://github.com/adamralph/bullseye with https://github.com/adamralph/simple-exec or https://nuke.build/.

[macrogreg]

@andrewlock is working on this on the Datadog side.

making @zacharycmontoya the owner just to keep this racking item up to date.

[zacharycmontoya]

PR introduced in Datadog repo: DataDog/dd-trace-dotnet#1476

This will likely require further iteration

[zacharycmontoya]

The initial PR has been merged: DataDog/dd-trace-dotnet#1476

[pellared]

Done.