Basic action card, w/ source editor, subscribed to URL string and WebView widget

[matthewryanscott]

This is just to get things started toward the path of having a list of action cards wired together.

The example source to include with the CodedWidget is up in the air.

My current thought is to have each action card aware of the shared WebView, independent of any I/O pipeline that is flowing through the cards. Each input type available is set by name, e.g. if an action card supported 'url' as input, then it should define an 'input_url' attribute.

So, something like this:

enamldef Main(Container):
    attr input_url = ''
    input_url ::
        url_editor.set_text(input_url)
    Label:
        text = 'URL:'
    TextEditor:
        id: url_editor