This change will allow to test beta and release candidate version of
postgres from apt.postgresql.org.
For stable version this change will make available the libpq package
for that specific version (that will not hurts).
This is a very very large change to the module. It started out as a fix to add
postgresl::server::config_entry, and quickly became a rewrite to fix a lot of
ordering issues inherent in the API.
Since this changes the Public API it is considered a backwards compatible
change.
See the upgrading guide in README.md for more details as to what has been
modified in this patch.
Signed-off-by: Ken Barber <ken@bob.sh>