fixup! Bug 27476: Implement about:torconnect captive portal within Tor Browser

Fixes #40497 (closed)

This changes how the homepage is navigated to on successful bootstrap. Bootstrap 'completetion' management is lifted into the TorConnect module, so only 1 instance of the homepage(s) are loaded. Additionally, the logic for opening multiple home pages is duplicated into TorConnect module. Old homepage and pref logic from aboutTorConnect.js has been removed.