chore: added editorconfig file

code/boot/.editorconfig

@@ -0,0 +1,24 @@
+# Editorconfig for Chibi PC-09 Firmware
+
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.s]
+indent_style = space
+indent_size = 2
+
+[*.md]
+max_line_length = 80
+
+[makefile]
+indent_style = tab
+indent_size = 4
+
+[justfile]
+indent_style = space
+indent_size = 4