Add splitter support for points and billboards in vector datasets

[na9da]

What this PR does

Merge after #7648

Adds splitter support for points and billboards in vector datasets.

Test me

• Open this CI link
• Verify that splitter works for points and billboards for CSV and GeoJSON datasets

Checklist

• There are unit tests to verify my changes are correct or unit tests aren't applicable (if so, write quick reason why unit tests don't exist)
• I've updated relevant documentation in doc/.
• I've updated CHANGES.md with what I changed.
• I've provided instructions in the PR description on how to test this PR.