Fixing some tests, make sure processed metrics are computed even if generic filters disabled, and do not apply queued filters in datatablemanipulators when fetching subtables.

Moved processed metrics computation to DataTableGenericFilter, removed new filters & implemented as methods in Report to avoid confusion regarding re-use, allow adding processed metrics as DataTable metadata and use this to rewrite AddProcessedMetrics filter, correct name of Metrics::getMappingFromIdToName function, added placeholder AggregatedMetric class for future, revise Metric/ProcessedMetric hierarchy (add methods for translation/etc.), allow .get API methods to use metadata to automatically figure out which columns to select, get EcommerceOrderWithItemsTest to pass.

Add more missing metrics from VisitFrequency.get API output (including max_actions_returning, nb_visits_converted_returning, etc.).

Add missing nb_users_returning metric to VisitFrequency.get Report metadata class so it will appear in 'processed' reports.

Because of IPv6 support, now two previously "unknown" visits are counted for US visits.

with tests
resolves #3581

refs #6511 fixed some tests which shows it seems to work now. I presume the expected results are correct but I do not know. Also updated another test where someone committed his path from his local server

refs #6519 added some missing test files as they were deprecated and can be executed now. I do not know whether the actual data is correct or not!