mod_invites_page: Fix templates including stray inviter name (thanks Menel) The util.interpolation syntax `{var?placeholder}` appears to have been intended as an if-not, but this syntax will always return either the variable or the placeholder-template.

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

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