Using issue tracker instead of built-in supported commit web link is based on the following reasons
* repo may have multiple remotes
* it is not good to open an context menu to choose which web to visit with multiple remotes
* some remote servers are not supported by this app
* 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.