Arvados

Currently, the logic for displaying 'loading' and 'notFound' indicators is implemented separately in several places (wherever it needs to be displayed). There is also a `NotFoundPanel` that displays when the route param (`/projects/*`, `/collections/*`, etc) is not found. It would be ideal if there were a global state, stored in redux, that would indicate the loading state of the resource whose UUID is in the URL, and possibly also the loading states of resources in the 'resources' slice of the redux store. This way any component that displays these indicators can just access the current state from the redux store and we can stop re-implementing the same logic as needed on an ad hoc basis.