Build ASP.NET Core cli tool packages from source to include in source-built SDK

[dagood]

This issue tracks investigating whether dotnet-dev-certs and similar ASP.NET Core tool packages can be included in source-build. If they can be, the tools can be included in the SDK and our product will be more similar to the Microsoft-built SDK.

Specifically, users wouldn't hit the "cannot find command" experience where they need to run dotnet install --global .... See #926 for an example of how this experience can require non-obvious workarounds.

[natemcmaster]

I would not expect this to be difficult for some tools, but doing it for all of them will be difficult. Here is my estimate, ordered from least difficult to most.

• dotnet-dev-certs
• dotnet-watch
• dotnet-user-secrets
• dotnet-sql-cache
• dotnet-ef

[MichaelSimons]

Closing as a duplicate of #428