* ui: Logout button
This commit adds an easier way to logout of the UI using a logout button
Notes:
- Added a Logout button to the main navigation when you are logged in,
meaning you have easy access to a way to log out of the UI.
- Changed all wording to use 'Log in/out' vocabulary instad of 'stop
using'.
- The logout button opens a panel to show you your current ACL
token and a logout button in order to logout.
- When using legacy ACLs we don't show the current ACL token as legacy
ACLs tokens only have secret values, whereas the new ACLs use a
non-secret ID plus a secret ID (that we don't show).
- We also added a new `<EmptyState />` component to use for all our
empty states. We currently only use this for the ACLs disabled screen to
provide more outgoing links to more readind material/documentation to
help you to understand and enable ACLs.
- The `<DataSink />` component is the sibling to our `<DataSource />`
component and whilst is much simpler (as it doesn't require polling
support), its tries to use the same code patterns for consistencies
sake.
- We had a fun problem with ember-data's `store.unloadAll` here, and in
the end went with `store.init` to empty the ember-data store instead due
to timing issues.
- We've tried to use already existing patterns in the Consul UI here
such as our preexisting `feedback` service, although these are likely to
change in the future. The thinking here is to add this feature with as
little change as possible.
Overall this is a precursor to a much larger piece of work centered on
auth in the UI. We figured this was a feature complete piece of work as
it is and thought it was worthwhile to PR as a feature on its own, which
also means the larger piece of work will be a smaller scoped PR also.
John Cowen