AIP-84 Add UI batch recent_dag_runs endpoint

[bbovenzi]

In the new Dags list view we show a chart of recent dag runs:

We should add a new endpoint ui/dags/recent_dag_runs to return an array of recent dag run arrays like so:

[{ dag_id: 'string', dag_runs: []}]

It should accept the same filters and pagination as the public get dags endpoint so that we can match them together.

This replaces the viewspy /last_dagruns.

[jason810496]

Hi, I've just finished #42713. Could you please assign this ticket to me? Thanks!

[bbovenzi]

@jason810496 all yours!