remove resolver recipe and attributes

The default AWS DNS servers are fast, and properly resolve the EC2
internal network hostnames and FQDNs

* Remove the resolver recipe from the system_tools role
* Remove the resolver attributes from the base role
move pg_hba and listen_addresses attributes to recipe

The recipe is a better place for these attributes as they contain
dynamically detected data.

* listen_addresses should use *this* node's IP address
* pg_hba should use information from the application-specific data bag
(easier to change)
dynamic redis configuration and better password handling

* The data base password is stored in a data bag that doesn't live in
the source repository.
* Load the secrets data bag for the database password
* tell redis to listen on the node's ip address, and search for the
redis node in the app recipe
move the redis detection over to the environment_variables

The environment_variables recipe handles setting the redis url, so
perform the search there.
attribute? is a node method
reorder so attribute is picked up
use proper hash key for REDIS_URL