Switch to Jotunn's GUI helpers

[sweetgiorni]

AnyPortal 2.0.0 switched to Jotunn, but it still uses ugly hacks to manage the GUI. Specifically it creates new inputs fields using a template prefab and renders them on top of the default TextInput. It also hides the default "OK" and "Cancel" buttons shown by the TextInput panel.

This ticket is to get rid of as much custom GUI code as possible by using the GUI helpers provided by Jotunn.. If the GUI can be defined and managed programmatically it should supplant the need for a prefab and allow us to completely get rid of the current asset bundle and Unity project. This would dramatically simplify the project.

The new interface should not automatically put keyboard focus on the portal name input. That's what the current field does and it makes it too easy to change the portal name by accident.