Update .editorconfig

- Specify indentation of 4 spaces for js/ts/md files, 2 spaces for
  json/yml files.
- Specify LF end of line, final newline and use of spaces for all files.

Signed-off-by: Simon Marchi <simon.marchi@ericsson.com>

.editorconfig

@@ -1,7 +1,12 @@
 root = true
 
-[*.{json,js,ts,md,yml}]
+[*]
 insert_final_newline = true
+end_of_line = lf
+indent_style = space
 
-[.gitignore]
-insert_final_newline = true
+[*.{js,ts,md}]
+indent_size = 4
+
+[*.{json,yml}]
+indent_size = 2