[#4397]+[#4344] Move type-name resolution out of Puppet::Resource into the AST resources.

Move type-name resolution out of Puppet::Resource into the AST resources.
Move find_resource_type out of Puppet::Resource into Scope
Thus, never pass unqualified type names to Puppet::Resource objects.
Thus, Puppet::Resource objects don't need the namespace property,
and Puppet::Resource objects never consult the harddrive to look for
.pp files that might contain their type definitions,
Thus, performance is improved.

Also removes the temporary fix for #4257 that caused #4397
(The code was too eager to look for a class in the topscope)

Paired-With: Paul Berry <paul@puppetlabs.com>
Signed-off-by: Jesse Wolfe <jes5199@gmail.com>