EmissionManager: Implement pagination when editing schedules

In EmissionManagerModalEdit.vue when we click on a timeslot, all the other timeslots in the schedule get listed, for the user to check and decide on what to do with the selected timeslots and all other timeslots in the same schedule.

When the schedule contains a lot of timeslots, one has to scroll down until the end of the list in order to decide what to do.

For this we should implement pagination of those timeslots. Probably quite easy when using a table instead of a simple list.