Refine navigation

[timja]

Start shuffling things around a bit as a precursor to #749.

The most common action a user would do when going to the role strategy plugin is assigning roles, so make that page the entrypoint.

Changes:

• Migrate to using the app bar for navigation
• Remove sidepanel
• Rename the management link from Manage and Assign Roles to Role Management
• Moved macros link to under role name so its in context helping people know where to use it

Testing done

clicked all links looks fine

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed

[timja]

possible to 🚢 this and the other ready ones please?