party: fix activity_object referencing

Signed-off-by: Imre Deak <imre.deak@intel.com>
api: activity_scores: add missing activity time

Signed-off-by: Imre Deak <imre.deak@intel.com>
api: move parse_date_from_opts earlier

Signed-off-by: Imre Deak <imre.deak@intel.com>
activity_counts/scores: add support for time range filtering

Signed-off-by: Imre Deak <imre.deak@intel.com>