Fix NickServ language crash; convert four ChanServ binary options to level options

Fix NickServ language crash; convert four ChanServ binary options to level options

* When you use "/msg nickserv set language" and you have no language
assigned, it would crash.  Fix this.

* Convert four ChanServ binary options to level based options:
  * Voice (CHANNEL_VOICE_ALL) -> Voice (lvlGiveVoice)
  * UserInfo (CHANNEL_INFO_LINES) -> UserInfo (lvlUserInfo)
  * PeonInvite (CHANNEL_PEON_INVITE) -> InviteMe (lvlInviteMe)
  * TopicSnarf (CHANNEL_TOPIC_SNARF) -> TopicSnarf (lvlTopicSnarf)

* Document the changes in ChanServ options.
git-archimport-id: srvx@srvx.net--2004-srvx/srvx--devo--1.3--patch-20