mod_http_oauth2: Improve handling of redirect_uri matching and fallback Per OAuth 2.1, the client MUST provide a redirect_uri explicitly if it registered multiple. If it only registered a single URI, it may be omitted from the authorize request.

This module lets you block connections to any remote servers not on a
whitelist.

``` {.lua}
modules_enabled = {
    -- other modules --
    "s2s_whitelist",

}
s2s_whitelist = {
    "example.org",
}
```