* Only allow to start interactive rebase from merged commit in current branch
* The order of commits in the interactive rebase window is as same as it's in histories page.
* Unlike anthor git frontend app `Fork`, you should edit the final message on the last commit rather than the previous commit that will be meld into while squashing commits
* 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.
