Connect Account to Web Page

[sondreb]

Whenever the user responds to an "action", they must initially pick an account they want to assign to the web page. E.g. if the web page asks the user to perform a signing, they must first pick account, even though there is already an active account open.

The next time any "action" is triggered from the same domain, the extension will auto-select the previous account.

We must ensure we have some UI where user can "logout" their account from specific web pages.