build: add editorconfig for kotlin

.editorconfig

@@ -14,3 +14,12 @@ indent_size = 2
 [*.md]
 indent_style = space
 indent_size = 4
+
+[*.{kt,kts}]
+# possible values: number (e.g. 2), "unset" (makes ktlint ignore indentation completely)
+indent_size=4
+# true (recommended) / false
+insert_final_newline=true
+# possible values: number (e.g. 120) (package name, imports & comments are ignored), "off"
+# it's automatically set to 100 on `ktlint --android ...` (per Android Kotlin Style Guide)
+max_line_length=off