DCB Rest API Updates

DCB Rest API fixes and updates, including new 'history' and 'search' APIs.

• 'backupStatus' should return 'success' or 'failed'. Note, assumption that currently there is NO 'no backup' status - if there are any records in 'device_config' table, then they are 'success' or 'failed'. In future this may change if we track devices that have been provisioned but no backup attempts have yet been made, OR if devices that have never had a successful backup should be classified as 'no backup' instead of 'failed'
• 'device-config' API should only return latest entry per ipinterfaceId
• Update code that determines "Content-Range" to do a requery that gets just the count, not the records themselves (query performance improvement) (will be handled in future PR)
• New 'device-config/history/{ipInterfaceId}' API should return history for given ipInterfaceId, but only return items containing 'config'. Default sorting by lastBackupDate DESC (currently handled in this PR by 'device-config/ipInterfaceId={id}', may eventually move to separate 'history' API to make intention clearer)
• New 'device-config/search?query={query}' API to search by deviceName and/or ipAddress, return by lastUpdatedDate DESC (handled in this PR by 'device-config?search={searchTerm}')