Adds namespace support to the UI:
1. Namespace CRUD/management
2. Show Namespace in relevant areas (intentions, upstreams)
3. Main navigation bar improvements
4. Logic/integration to interact with a new `internal/acl/authorize` endpoint
ui: Repo layer integration tests for methods that touch the API
Includes a `repo` test helper to make repetitive tasks easier, plus a
injectable reporter for sending performance metrics to a centralized metrics
system
Also noticed somewhere in the ember models that I'd like to improve, but left
for the moment to make sure I concentrate on one task at a time, more or less:
The tests currently asserts against the existing JSON tree, which doesn't
seem to be a very nice tree.
The work at hand here is to refactor what is there, so test for the not
nice tree to ensure we don't get any regression, and add a skipped test
so I can come back here later
1. Listing, filtering by action and searching by source name and
destination name
2. Edit/Create page, edits ping the API double fine, need to work through
creates and deletes
3. Currently uses a `Precedence` intention keyname that doesn't yet
exist in the real API
