Redirects the user to a nearby mirror site.
An instance is mirrors.moe.
The configuration is a JSON file and should be specified with the -conf option when running mirrorhub.
It should be an object with the following members:
sites: an object mapping site names to site configurations, where a site configuration is an object with the following members:
url: the full URL for the site. A trailing slash is not needed. Example: https://mirrors.ustc.edu.cn
distros: a list of distros available on the site.
routes: a list of routes, where every route is an object with the following members:
ipnet: an IP subnet in CIDR notation.
ordering: an ordering of site names appropriate for this subnet.
default-ordering: the default ordering of sites.