Assignment UI - Always show all options (add schedule, content review) with description on how to enable

It came up on a call that it would be useful if all of the options were shown to the instructor even if they weren't usable for some reason, probably just as static or unselectable text. And then provide some extra description on how you could enable them.

This would be good for advertising content review services, reducing support requests for why certain options aren't appearing.

This comes up pretty often in jiras like https://sakaiproject.atlassian.net/browse/SAK-29295#icft=SAK-29295 where you need to add calendar tool to see the checkbox, or you need to enable a content review service to see that option. Or you probably need to add Gradebook before that comes up too.

I'm not sure if we'd need a property to enable this, or how we'd go about "advertising" the content review services, but I think it would be helpful.