When user logs in, new session should be started with editor closed

[dnaidionov]

Application remembers last state and, when user logs in, restores it. However, if users log in on the community page, or different article than they logged off from, they might be brought straight into the edit mode. We should start new session with closed editor, and edit mode off.
This was addressed in cardstack/dotbc#288 and cardstack/dotbc#284
However, I think we need to go deeper than this, and to turn off edit mode when user's session is terminated (either on log off or timeout) as leaving it might bring to unwanted side effects (e.g. user will continue seeing placeholders while being logged off)
Those are 3 related problems and will be tracked in 3 separate issues

This issue addresses starting new session with editor closed