[URI4Files] Go - Implement loading of Device Service files (Profile, Device and ProvisionWatcher) from URI

[lenny-goodell]

See https://docs.edgexfoundry.org/3.0/design/adr/0027-URIs%20for%20Files/#servicesfiles-impacted

If ProfilesDir/DevicesDir/ProvisionWatchersDir setting value starts with http:// or https:// then use new LoadFile to get the list of files to load. Then iterate through the list calling LoadFile for each file in the list. Each file URI is built from the original URI replacing the index.json with the filename from the list. The edgexSecretName query parameter, if present, must be retained.