Add support for localName based filtering in PfReferenceTimestamp key.

Issue : Currently we have a requirement to filter control loop
statistics based on the UUID of the element which is "localName" of the
PfREferenceTimestamp key. Adding UUID as part of filterMap in
getFiltered() method which also requires this minor change in buildFilter.

Issue-ID: POLICY-3051
Signed-off-by: zrrmmua <ramesh.murugan.iyer@est.tech>
Change-Id: Idb9f4fc47c439f84bf8fc784bd9e228a2e05d8e9