Allow more options to be configured in the config template

Several options like `host_base` and `host_bucket` usually need to change when the `bucket_location` is overridden. I've also allowed `encrypt` to be configured.

Configuring the `filename` is required where a user may have multiple config files that they use with the `s3cmd -c` switch.

I've also allowed s3cfg files to be created purely with hiera by auto-loading anything under the `s3cmd::config` hash. I find this is really convenient for the majority of cases that just want to define a couple of access keys in hiera and move on, without having to change any puppet code for the next change.