move conf.DefaultServerFrontendOnly to cmd/frontend
Created by: ggilmore
This PR does not need to update the CHANGELOG because there are no user-facing changes.
- move the definition of the server struct to
cmd/frontend/globals
to prepare for that logic to read directly from postgres - Move files related to parsing and the config store to their own subpackages to avoid circular import issues / deadlock between
cmd/frontend
pkg/conf