* Update form .NET Core 2.2 to .NET Core 3.1
- Global variable for projects
- Change TFMs from netcoreapp2.2 to netcoreapp3.1
- Update global.json
- Update build.json
- Remove direct framework cake TestCore task
- Update travis dotnet version
- Update azure pipline file
- Update vscode launch.json
* Add Central Package Management
* Fix xUnit Breaking Change for MemberData type
* Fix xUnit breaking change for duplicate test method name
* Fix Rang/Index type conflict with System.Rang/Index
* Update vscode tasks.json
* Change serviceHostExecutable path in ServiceTestDriver.cs
* Downgrade SDK version (https://github.com/appveyor/ci/issues/3440)
- Appveyor hasn't installed latest SDK therefore I downgrade it until they install it.
* Dump Microsoft.SqlServer.DACFx
This should really be combined into a single pipeline file with the build like we do for ADS but for now just fixing this so we can have the releases published again.
- Use global.json to control what version of .NET SDK is used for building so local builds also use the version used for pipeline builds
- Add some missing items to the sln so they are viewable through VS
- Delete extra project file
