Add alerts for low redundancy and low allowance funds

MERGE REQUEST

Overview

This MR adds 2 more alerts to the renter/contractor

Changes to Work Flow

2 more alerts were added. One of them is registered if a contract fails to be formed or renewed due to low funds and unregistered the next time threadedContractMaintenance runs without issues which originate from low funds. The other one is registered if the health loop encounters a file with less than 75% of redundancy remaining and unregistered when the file is encountered again with >75% redundancy.

Testing Changes

testLocalRepair was updated TestLowAllowanceAlert was added

Documentation Changes

N/A

Modules and Packages Impacted

modules/renter, siatest/renter, modules/renter/contractor, modules, modules/renter/siafile

Example for Visual changes (ie Screenshot)

N/A

Issues Closed

N/A

Checklist

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

• Pipeline Passing (this is for NDFs where tests were run in a loop)
• All new methods, or updating methods have clear docstrings
• Testing added or updated for new methods
• API documentation updated for API updates
• Module README.md updated for changes to work flow
• Issue added to Sia-UI repo for new supporting features