Draft: Change Registry Subscription code to use a bandwidth limit

MERGE REQUEST

MR Guidelines

Overview

This MR changes the registry subscription protocol a bit. It will no longer request an EA payment for each request. Instead the initial request will be used to fund a "budget" which is then used to pay for requests and bandwidth. Even the request to extend the subscription is paid for using that budget.

Should the renter run low on money in the budget, they can issue a "prepay" request which acquires a lock on the subscription info. This means no notifications will happen during this time to make sure the renter and host agree on the remaining budget at the time of updating it. Once done, the host will send a notification to the renter.

Checklist

Review and complete the checklist to ensure that the MR is complete before assigned to an approver.

• All new methods or updated methods have clear docstrings
• Testing added or updated for new methods
• Any new packages are added to Makefile and .gitlab-ci.yml
• API documentation updated for API updates
• Module README.md updated for changes to workflow
• Issue added to Sia-UI repo for new supporting features
• Changelog File Created

Issues Closed