### What
Add workflow for refreshing a payment collection.
The idea is that on all cart updates, we want two things to happen (in the context of payments) 1. the currently active payment sessions should be destroyed, and 2. the payment collection should be updated with the new cart total.
We do this to ensure that we always collect the correct payment amount.
From a customer perspective, this would mean that every time something on the cart is updated, the customer would need to enter their payment details anew.
To me, this is a good tradeoff to avoid inconsistencies with payment collection.
Additionally, I updated the Payment Module interface with `upsert` and `updated` following our established convention.
### Note
This PR depends on a fix to the `remoteJoiner` that @carlos-r-l-rodrigues is working on.
Update: Fix merged in #6602
Co-authored-by: Adrien de Peretti <25098370+adrien2p@users.noreply.github.com>
~~Opening a draft PR to discuss a couple of implementation details that we should align on~~
**What**
Add workflow and API endpoint for creating payment sessions for a payment collection. Endpoint is currently `POST /store/payment-collection/:id/payment-sessions`. I suggested an alternative in a comment below.
Please note, we intentionally do not want to support creating payment sessions in bulk, as this would become a mess when having to manage multiple calls to third-party providers.
