UI Conversion: Cleanup margins / paddings
UI Conversion: Cleanup margins / paddings

Summary:
Cleaned up margins and paddings by removing hardcoded values and use constant sizes from "themes" instead.

Changelog: Database plugin UI aligned with the new Flipper UI

Reviewed By: mweststrate

Differential Revision: D28094217

fbshipit-source-id: 6514b2f1ea7073ca658a86e49c2be029f054ddf0

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper