Contrib, schema, and load_module

Folks,

Magnus and I decided to take on the annual /contrib cleanup for the code
sprint here at pgWest. One of the areas we realized needs cleanup is
the use of schema with the modules -- Magnus, Bruce and I all think that
contrib modules really need to create and use their own private schema.
Reasons:

-- user access to specific modules
-- backup/restore
-- upgrading modules
-- namespace conflicts (currently, we don't test for these)

However, this brings up some questions:

1) should the private schema names be "module_name" or "pg_module_name"?
If the latter, what about pgbench and pgcrypto?

2) how do we give DBAs an easy search path for the simplest case, where
they want all users to have access to all loaded modules?

3) what work was actually done on load_module() by Tom Dunstan, which
might make this unnecessary?

--Josh Berkus