Understand whether I'm connected

As a web3 user, I'd like to understand whether I'm connected to a site, so that I'm not confused about what the connection statuses in MetaMask mean.

**Description**

When a user is "Not connected" currently, some users mistakenly believe this means their internet conection is down or MetaMask can't connect to Infura.

Instead, we should have new states for the connection statuses of sites:

1. Not connected: display nothing in the top left (there is no connection button anyways)
2. Connected on a different account - yellow dot, show truncated domain
3. Connected - green dot, show truncated domain

**Acceptance criteria**

* On hover of a truncated domain, show the full domain name.

Start by locating the MetaMask UI that renders site connection statuses and inspect how the current “Not connected” state is displayed. Trace the existing account and site data used there, then verify the three requested visual states and that hovering a truncated domain shows its full name.

Written by the indexing model from the issue text.