Invalid uses of `{{outlet}}` should throw

[chancancode]

1. Using {{outlet}} in anything other than a route template (e.g. components)
2. Using {{outlet}} inside the application template of a non-routable engine ({{mount}})

[jelhan]

Should be covered by ember-template-lint/no-outlet-outside-route, isn't it?

[kategengler]

I don't think we actually want to do this. We're giving Routing a rethink but also we now have Glimmer Components as Route Templates.

[NullVoxPopuli]

additionally, I think people are using outlet outside of route templaets -- but also route templates can be components now, so I'm not sure this issue still makes sense.

will close for now