Add pagination to the UI when viewing splits.

When working with the UI I noticed we fetch all splits at once when displaying splits on the UI. With a large number of splits, this request is very slow and eats up a lot of memory on the browser.

Introducing pagination would let us reduce how much data we're fetching on the single page load while still letting users view all their splits if they wish to do so. This also should reduce any side effects of issuing a heavy request to the metastore.

Locate the UI entry point that displays splits and trace the request that currently fetches them all at once. Read how the split list and metastore request are wired together, then verify that users can move through pages while the initial request retrieves less data and large split lists remain usable.