385 categorized layers

[redhog]

Connects https://github.com/GlobalFishingWatch/pelagos-client/issues/385

To test:

• Go to advanced mode
• Go to edit mode
• Expand one of the animations
• Click on the [empty] value right of "Category:"
• Enter a new category name
• Press enter

The animation should now be moved to a new tab with the name you entered.