* rename `FirstParentFilterToggled` to `EnableFirstParentInHistories`
* remove `FirstParentFilterEnabled` from repo settings - it should not been saved
* move toggle button from repository toolbar to histories switcher
* tooltip translations
* new icon for `Icons.FirstParentFilter`
* extends commit graph to support `--first-parent` option
* 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.
