Drag-and-drop to reorder subreleases within master release Merged

On the releases roadmap, subreleases are shown in the order in which they were added to the master release. The release date, development start date, phase dates, etc. have no impact on the display order for subreleases. The only way to alter the order is to go into each subrelease, detach it from the master release, and then add them back in the correct order. If dates change, this cumbersome process has to be repeated each time.

The order of subreleases within a master release should either be tied to one of the date fields or the master release details screen should include drag-and-drop reordering functionality for subreleases.