Add .editorconfig based on Meson's

Author: xclaesse

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.py]
+indent_size = 4
+
+[meson.build]
+indent_size = 2
+