Implement a event sampler that can also filter on tables conditions.

Implement a event sampler that can also filter on tables conditions.

The script :

• filters the events in the "sampling files" based on the input condition
• samples n events among the filtered events
• Copies the sampled events from the "copying files" to the output file. Events are retrieved in the copying files based on their event_id. The assumption is made that there is a 1 to 1 map between the copying and sampling files, and that their index in the file list of their respective folder matches.

Also: move the unit tests inputs in tests/resources instead of in the wiki, and track them with git lfs.