mtarget UI revamp

[frzyc]

• [x] - convert the configs into cards with popups, instead of accordions (its not possible to fit 2 configs in the same screen realistically, no point being able to show multiple)
• [x] - separate the "import" from "export" (no more persistent JSON textbox, only shown on import)
• [x] - Remove ability to reorder configs (no point if several can fit in the page. we can address sorting later once we establish the new flow)
• [ ] - being able to drag and drop reorder on targets in a config.
• [x] - reduce generally what's shown in a target, so config with multiple targets are less noisy(probably only show the target, weight, and crucial info, and make it an accordion that shows detail on-click)
• [x] - allow adding description to targets (shown with hoverable (i))