Add ClickName parameter on Buttons, to change value when clicked

[Badgerati]

When a Button is clicked, a spinner will appear to show that it is processing. What could also be useful is to have a -ClickName parameter which will change the value on the button as well, when clicked. When the processing is done, the callback to update the value back to the -DisplayName will need to occur before any actions are processed.

For example, when clicked it will go from Submit to Submitting, or from Create to Creating.

This is just for New-PodeWebButton, but potentially worth investigating Forms and Steps as well.