Homepage Posts block: Sort specific stories

[gamebits]

Is your feature request related to a problem? Please describe.
When multiple specific posts have been assigned to a Homepage Posts block, changing the order in which they appear requires removing and re-adding them.

Describe the solution you'd like
The ability to order or drag-and-drop the stories would allow the stories to be sorted without first removing them.

Wrote one Newspack publisher:

this would be an important efficiency to have available in periods of frequent updating, although [we] curate the top area of their home page several times a day so this would pay off in regular posting times as well.

Describe alternatives you've considered
One alternative is to have separate Homepage Posts block, one for each story, and use Gutenberg's list view to drag-and-drop the blocks themselves.

Additional context

[gamebits]

See also Asana: 1200550061930446-as-1203781871464058