Add .editorconfig

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = tab
+indent_size = 8
+max_line_length = 80
+
+[*.xml,meson.build,meson_options.txt]
+indent_style = space
+indent_size = 2
+tab_width = 8