refactor<*>: rewrite all with AvaloniaUI

src/Commands/QueryRepositoryRootPath.cs

@@ -0,0 +1,15 @@
+namespace SourceGit.Commands {
+    public class QueryRepositoryRootPath : Command {
+        public QueryRepositoryRootPath(string path) {
+            WorkingDirectory = path;
+            Args = "rev-parse --show-toplevel";
+            RaiseError = false;
+        }
+
+        public string Result() {
+            var rs = ReadToEnd().StdOut;
+            if (string.IsNullOrEmpty(rs)) return null;
+            return rs.Trim();
+        }
+    }
+}