Payment Reminder Dialog

Premise: We want 3rd party devs to get paid for their apps. Traditional open source users get pissed off about paying up front for things. We need a way to provide a payment "time bomb". A kind of reminder to pay. It needs to be easy (one click), in app, secure, etc.

We should create a standard Payment Reminder Dialog that does the following:
* Provides a standard message and layout so that users become familiar with the dialog and trust it's origin
* Ties into elementary accounts, specifically for payment so that users don't have to enter payment details into a dialog from an app they've never heard of until a bit ago.
* Features a simple method to choose a payment amount from "Never show me this dialog ever again" to whatever you want to pay.
* Knows if a user did already pay for this version on any of their devices and doesn't bug them again (once again, elementary account).
* Only reminds someone to pay if they actually use the app fairly frequently. Not just number of times (you opened it twice!) or length of time (it's been a month!) but actually, "Hey you seem to use this app at least once a week".
* Knows the difference between a major update and small release and reminds users to keep paying when a major release comes out to ensure more major releases are made.
* Can be globally disabled


* ATTENTION *
If you're about to tell me how devoid I am of morals and how wrong and ungrateful and arrogant I am for suggesting that we help 3rd party developers eat, just please stop and go away.

Also, as explained many time, "donation" carries certain legal connotations (like tax exemption). Since we are not a legal non-profit entity and it would be needlessly complex to verify non-profit status of every third party developer (which is basically 0 of them) it would be misleading (read: lying) and could potentially get us in legal trouble to use the word "donation". The correct term is "payment". I don't care if this word offends you, it's not honest to use any other word.