bunch of stuff

administration.lua: everything's better; automatic migration.
database.usernames -> database.users. View with /me.
Nicks and lastfm usernames moved to database.users; auto migrate.

config.lua

@@ -15,7 +15,6 @@ return {
 	-- If you change this, make sure you also modify launch-tg.sh.
 	cli_port = 4567,
 	admin = 00000000,
-	admin_name = 'John Smith',
 	log_chat = nil,
 	about_text = [[
 I am otouto, the plugin-wielding, multi-purpose Telegram bot.