Changes:
* This removes MSBuild targets which invoke `docker` commands to build
deb and rpm installers
* Remove installer targets from the KoreBuild context. Put them into
separate project files
* Simplify the targets used to build installers by reducing duplicate
variable names and deeply nested MSBuild contexts
* Remove unused dependencies from the Docker build context
* Disable package analysis because it incorrectly issues NU5109 on macOS, but not windows
* Normalize file paths because if you mix slashes, NuGet will just skip the entire folder
* Normalize the project path given to restore. If it not normalized, restore skips the project and issues a warning
This refactors the targets used to build the shared framework and its .zip files. There are lots of reasons motivating this: Arcade convergence, migration to VSTS, making it easier to build this locally, etc.
Changes:
* Moves move content of build/Sharedfx.{props/targets} into eng/targets/SharedFx.Common.{props/targets}
* Update the build to produce a `runtime.$rid.Microsoft.AspNetCore.App` package (not just the one with symbols in it)
* Refactor the targets which produce .tar.gz/.zip files into separate projects in `src/Installers/`
* Refactor installers, unit tests, and the framework projects to use ProjectReference to flow dependencies between different parts of the build.
* Makes it easier to build the shared framework locally (for the inner dev loop, you can run `dotnet build -p src/Framework/Microsoft.AspNetCore.App/src/ -r win-x64`)
This code previously was in private repos because it had references to internal locations and drop shares. This code has been modified to remove these internal-only pieces.