conf: Options of all plugins documented

Some options are still missing descriptions though.

conf/plugins/eap-tls.opt

@@ -0,0 +1,8 @@
+charon.plugins.eap-tls.fragment_size = 1024
+	Maximum size of an EAP-TLS packet.
+
+charon.plugins.eap-tls.max_message_count = 32
+	Maximum number of processed EAP-TLS packets (0 = no limit).
+
+charon.plugins.eap-tls.include_length = yes
+	Include length in non-fragmented EAP-TLS packets.