chore: add .editorconfig and .gitattributes

Author: Seungpyo1007

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+
+[*.py]
+indent_style = space
+indent_size = 4
+
+[*.{json,yml,yaml,md,html}]
+indent_style = space
+indent_size = 2

.gitattributes

@@ -0,0 +1,3 @@
+# Every tracked text file is stored with LF; keep working trees the same on
+# Windows and macOS.
+* text=auto eol=lf