Avoid excessive host deletion in hostdb

MERGE REQUEST

Overview

This MR addresses an issue in the hostdb where an excessive number of hosts was being deleted. This was found on Skynet portals which have a large number of contracts which were unusable because their host was deleted from the hostdb for bad uptime.

• Don't delete hosts we have a contract with from hostdb
• Initiate a rescan on startup if a host in knownContracts isn't in the host tree
• Increase maxHostDowntimefrom 10 days to 20 days

Test can be verified by commenting out the line that adds the host to knownContracts.

Example for Visual Changes

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