Improve the warnings for users not confirmed yet

Instead of showing a warning on every single page load, shows a permanent
warning on the home page and on the account settings page.
Didn't change how confirmation works, just changed the warnings.

Cherry-pick of 9f905cd736d14c7dffb0e95c951ae1f2fd22c040
Needed to pull this commit to this branch to update a test server without
having to merge everything else.

Conflicts:
	app/controllers/application_controller.rb