[development] Site credits module

[Moshe Weitzman]

Chris Johnson wrote:
> Interesting and useful idea, Moshe.  I'm not quite seeing why it would
> be a core module, though.  Interested in hearing why.

a big part of this proposed module is about teaching others how to build a 
site like yours. if knowledge sharing is a core part of drupal, then this 
module is a candidate for core. we shouldn't really debate this point much, 
since !module_exists().