* remove unnecessary namespace using
* move `Commands.Branch.HasRemote` to `Commands.Remote.HasBranch`
* remove `Commands.Branch.DeleteRemoteTracking` and check branch in `Commands.Branch.DeleteRemote` directly
Signed-off-by: leo <longshuang@msn.cn>
* remove dotnet-tool.json because the project does not rely on any dotnet tools.
* remove Directory.Build.props because the solution has only one project.
* move src/SourceGit to src. It's not needed to put all sources into a subfolder of src since there's only one project.