Add .editorconfig

... copied from the main Theia repo.

Signed-off-by: Simon Marchi <[email protected]>

Author: Simon Marchi

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+insert_final_newline = true
+end_of_line = lf
+indent_style = space
+
+[*.{js,ts,md}]
+indent_size = 4
+
+[*.{json,yml}]
+indent_size = 2