Expose size as theme variables for create and edit popup

While we aren't able to tackle complex forms topic, we still have some customers that have big creation forms which is not compatible with the current create form popup.

Goal is to expose the height and width of the popup so it can be changed in the theme.

It should include:

• adding the default values to all themes (as Designer use them to clone and customize)

• add default value (when theme var is not set)