Field can't handle <script> tags

[dkrasner]

main issue

The DOM parser is very greedy with the </script> tag and will grab even if it is inside a string (quotes), such as the value of an innerHTML property. This causes our de-serialization to fail, and is annoying in case you are using the field to write vanilla js/html.

We should probably have a special code editor part which subclasses field, or rework field, or remove DOM parsing from the serialization all together and only save the serialization/JSON itself. (Or all of these)