Add locale parameter support

This adds the parameter 'locale' to the 'postgresql' class so we have a global
default, and adds it two the defined resources 'postgresql::db' and
'postgresql::database'. This allows users to either:

* Defined a global default for the cluster
* Define a per-database default

As a side-effect I had to make sure 'charset' was also exposed in a similar
manner as some locales need a particular charset to work.

Tests were added to test both the 'createdb' case and 'initdb' case for Redhat,
and some refactoring was done to make the existing non_default test area use
heredocs so my manifests and test code was kept close together. As apposed to
entirely different files and places in the directory structure.

I cleaned up the related execs a little bit, adding logoutput => on_failure
where needed so we can debug failures. Beforehand execs just 'failed', but
now we should be able to get better feedback from failed execs helping support.

I also add intention comments in parts of the Puppet code that I touched where
it made sense.

Signed-off-by: Ken Barber <ken@bob.sh>