mod_http_oauth2: Fill in some client metadata defaults Explicit > Implicit Maybe we should actually use these for something as well? :) It's is somewhat an open question of how strictly we should enforce things in the client metadata given that it is somewhat extensible. Especially some of these enum fields which have corresponding IANA registries.

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",
}
```