Simple hot-desking

I've added an Asterisk recipe for simple hot-desking to the wiki. This is valuable when the number of phones don't equal the number of users (i.e., 24x7 call centers) or your users tend to not have the same desk from day to day (temp workers or those on travel). What's in the wiki is quite basic (uses Asterisk's built-in database) but it can be easily adapted to facilitate some elegant click-to-call web interfaces for multiple teleworkers.