Code editor widget (ui.editor?)

[mofojed]

We should have an editor component that can be used with deephaven.ui. Right now the closest thing is ui.text_area which does not have any syntax highlighting or autocomplete. Some suggested functionality:

• Prop for setting the language of the editor
• BONUS: For onChange, could have a LSP on the server side to update the model using deltas rather than re-sending the enter file each time

[dsmmcken]

I would name it ui.code_editor I think.