[sr-dev] TLS docs

<title><varname>config</varname> (string)</title> <para> Sets the name of the TLS specific config file. </para> <para> If set the TLS module will load a special config file, in which different TLS parameters can be specified on a per role (server or client) and domain basis (for now only IPs). The corresponding module parameters will be ignored. </para> Is this still valid - that we only configure tls on IP? /O