Improve Run Instances Dialog

[KoBeWi]

Small improvements to the dialog:

• moved main arguments and features to be next to each other
• added placeholders to clarify usage
• squashed instance count

Before:

After:

[seppoday]

I guess this kind of design might work?

[KoBeWi]

This makes the instance count disjointed from the list 🤔
Also the counter would be better on the left probably.

[Calinou]

I like @seppoday's mockup but I'd put the instance count on the left too.

[KoBeWi]

[akien-mga]

Looks good to me.

[akien-mga]

Thanks!