Standardise the unique IDs in various elara handler outputs

[syhwawa]

The names of attributes representing agent ids and link ids are inconsistent in some standard elara outputs. It is a bit misleading when user did some post-processing analysis using various elara outputs. I have looked through the elara outputs and summrize the inconsistencies IDs in the sheet named standardise_elara_output_ID.

As we discussed, here are some proposed rename Elara_IDs for different outputs. For example, we can use agent_id representing agent's ids. The link ids for various elara outputs from event handlers have been unified as in previous PR #224.

Elara Output Handlers	Elara outputs	Old Elara_ID	proposed rename Elara_ID	Example output
Event Handlers	link_vehicle_counts	link_id	link_id	1-2, 2-1
	link_vehicle_capacity	link	link_id	1-2, 2-1
	link_vehicle_speeds	id	link_id	1-2, 2-1
	stop_passenger_counts	link	link_id	1-2, 2-1
	link_passenger_counts	id	link_id	1-2, 2-1
	vehicle_passenger_log	agent_id	agent_id	gerry, fred
Done
Plan Handlers	trip_logs	agent	agent_id	gerry, fred
	activitiy_logs	agent	agent_id	gerry, fred
	leg_logs	agent	agent_id	gerry, fred
	leg_logs	seq	seq_id	1,2,3
	leg_logs	trip	trip_id	1,2,3
	plan_logs	pid	agent_id	gerry, fred
	agent_highway_distance_logs	agent	agent_id	gerry, fred
	agent_tolls_log	agent_id	agent_id	gerry, fred

It would be great to unify left inconsistent IDs in these plan handler outputs.

[syhwawa]

Hey @fredshone, here is a small issue that I mentioned in elara outputs. This is not urgent one and lease take a look whenever you have free time. Thanks.