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
Adds support for ACL Roles and Service Identities CRUD, along with necessary changes to Tokens, and the CSS improvements required.
Also includes refinements/improvements for easier testing of deeply nested components.
1. ember-data adapter/serializer/model triplet for Roles
2. repository, form/validations and searching filter for Roles
3. Moves potentially, repeated, or soon to to repeated functionality
into a mixin (mainly for 'many policy' relationships)
4. A few styling tweaks for little edge cases around roles
5. Router additions, Route, Controller and templates for Roles
Also see:
* UI: ACL Roles cont. plus Service Identities (#5661 and #5720)
