Closes#7197#7199
Note: Test coverage is limited to adapter and serializer unit tests. All
acceptance tests have been stubbed and all features have been manually
tested end-to-end.
This represents Phase 1 of #6993 which is the core workflow of CSI in
the UI. It includes a couple new pages for viewing all external volumes
as well as the allocations associated with each. It also updates
existing volume related views on job and allocation pages to handle both
Host Volumes and CSI Volumes.
Protect against case where an alloc has no services and avoid
dereferencing null.
Here, we ensure that the model and test serializers mimic the API by
having nil TaskGroup.Services instead of an empty array.
