Migrate Torque Explore curation CSS to LFCTheme

Styling for individual views (e.g., curation view) belong in LFCTheme, not Torque. This MR removes the styling from Torque.

⚠ This MR is codependent on these two:

• torque-sites!173 (merged)
• LFCTheme!24 (merged)

Addresses https://code.librehq.com/ots/clients/lfc/torque-tracker/-/issues/167