Add editorconfig

Author: kubo39

.editorconfig

@@ -0,0 +1,21 @@
+# EditorConfig: https://editorconfig.org/
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.d]
+indent_size = 4
+indent_style = space
+
+[*.{yaml,yml}]
+indent_size = 2
+indent_style = space
+
+[{CMakeLists.txt,*.cmake}]
+indent_size = 2
+indent_style = space