[API] Generate link to "chromeless" online payment page

[Glenn]

@Parker1090

One thing I have noticed, now I’ve got this work is that is still gives me the option to remove the Payment option even though I’m logged in as the client.

Mmm I see this, it’s showing these options, but will throw an error if you try clicking on them. It’s a very minor fix so I’ll try to get that corrected today or tomorrow am.