Partition list header should remain static at the top when scrolling

[sergio-costas]

When doing a manual partitioning, if there are too many partitions (for example, because there are several disks), and the partition list is too long to fit in the screen, scrolling it hides the column titles.

The column titles should remain fixed at the top, always visible.

This is how it is shown today:

This is how it should be rendered when scrolling down: