Introduce UI for showing requests across all tabs

Background / User story

Users can see which filters Adblock Plus applied for a given page by using our developer tools panel. However, this list is cleared whenever the page URL changes and is therefore not suitable for some use cases (e.g. to see filters that are applied to popups, redirects, background tabs or to a page before the panel was opened).

Therefore we could introduce a new UI page that displays all requests across all tabs and windows. For that we'll need to somehow indicate which page a request belongs to as well as a way to clear the list.

See also trac#6404, trac#4226 and trac#6044.

What to change

• Design: TBD
• Research: TBD
• Spec: TBD

Hints for testers

TBD

Hints for translators

TBD

Integration notes

TBD