This commit adds 2 ember component/helpers and a service to contain the
shared functionality for matching/rendering content dependent on state
identifiers. Currently a `service.state` method has been added to easily
make manual state objects, but these are built towards using `xstate` to
manage UI state in some of our future components.
We've added some tests here, and we aren't currently using these
components anywhere in this commit.
87ab332bce