Re-org Portal Navigation

This issue is about the re-arrangement of the portal's navigation, without major re-design, and intends to simplify the IA.

There are 2 parts of the update:
1. Update of navigations
2. Update of respective UI

## Problem

There are two types of actions that can be done in the portal: "Management" & "Configuration" but they are mixed in the navigation. The grouping of items is also poor, many users complained about the difficulty of finding the relevant pages.

## Solution

- Create distinction for the two intents, "Management" & "Configuration"
- Rename, merge, or delete the pages to simplify IA
- Improve the copywriting on each page

## Appetite

2 weeks for design and development

## Notes

This issue is to replace the obsoleted #901 , which was created a long long time ago. I want to take this opportunity for the designer to do some research and come up with the concrete design by themselves.

No files, tests, or entry points are named. Start by reviewing the portal's current navigation and page inventory, then define the Management/Configuration grouping, page changes, and copy. Done means an agreed concrete design plus the corresponding navigation and UI updates.

Written by the indexing model from the issue text.