Move logic out of components

[peterhil]

Tasks:

• [ ] Move logic from components into lib
• [x] Make operations async
• [x] Move some logic to the background page (high effort, questionable impact)

Consider:

• Does the logic apply to all tabs or just the current one?
• Not all things need to happen on background page – code might be more clear without indirections
• Aim is to make component code just represent the data and avoid blocking

Candidates to move to background:

• Searching
• Long lasting logic – all operations that take a while to complete
• Non async – possibly blocking operations