Create simple way to define sideEffects that are only triggered once

[taoeffect]

Problem

Some sideEffects we might only want to trigger a single time.

For example:

• #1400 might be an example
• Receiving "thank you" notifications for payments

However, at the moment sideEffects will get triggered each time we process the chain, in other words, each time we login to a new device or a browser we haven't logged in to before.

Solution

Design a way for single-use sideEffects to be defined.