feat: enforce code formatting with .editorconfig

.editorconfig

@@ -0,0 +1,16 @@
+# https://editorconfig.org
+
+# Declare this as the top-level EditorConfig file
+root = true
+
+# Set defaults (applicable for all files)
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+# [*.md]
+# trim_trailing_whitespace = false