dns/dsc: Improve out-of-box behavior

(From the PR) The sample configuration refers to an invalid PID
file location, and a non-existent data directory.

• Set PID file location to match RC script default
• Create default data directory
• While here, drop dependency on dns/dsp, which is not required to collect stats

PR: 245141
Submitted by: John W. O'Brien
Approved by: Leo Vandewoestijne (maintainer timeout, 2 weeks)