Verify `mirrors.json` against `mirrors.json.schema` when launching mirror

[carykees98]

Might be worth having a component that manages all interactions with the file mirrors.json including but probably not limited to

• Checking for live changes and sending the new config to other components.
• Making sure that the file matches the schema so that errors in the file are caught before it is too late.
• Single source of truth to prevent components from having varying versions of mirrors.json depending on when they are run and if they have a file watcher built into them.