[SD-463] Add linkset processor for site menus

[waitingallday]

Issue: https://digital-vic.atlassian.net/browse/SD-463

What I did

• Added processor to hydrate API response from drupal linkset endpoint
• Added unit test
• Refactored original menu_items processor

How to test

• Unit tests
• nuxt-app

Checklist

For all PR's

• I've added relevant changes to the project Readme if needed
• I've updated the documentation site as needed
• I have added tests to cover my changes (if not applicable, please state why in a comment)

For new UI components only

• I have added a storybook story covering all variants
• I have checked a11y tab in storybook passes
• I have added cypress component tests (if the component is interactive)
• Any events are emitted on the event bus using emitRplEvent

[cypress]

ripple-framework    Run #2427

Run Properties:   Passed #2427  •  170ff15a48: refactor(@dpc-sdp/ripple-tide-api): ♻️ use existing util

Project	ripple-framework
Branch Review	feat/linkset-menu
Run status	Passed #2427
Run duration	09m 26s
Commit	170ff15a48: refactor(@dpc-sdp/ripple-tide-api): ♻️ use existing util
Committer	Jason Smith
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	214
View all changes introduced in this branch ↗︎

[waitingallday]

Oops didn't leave any instructions to test this:

1. Backend with linkset enabled https://nginx-php.pr-1740.content-vic.sdp4.sdp.vic.gov.au
2. Endpoint is (e.g. vic main) https://nginx-php.pr-1740.content-vic.sdp4.sdp.vic.gov.au/system/menu/site-main-menu-vicgovau/linkset
3. Set in nuxt.config.ts

  runtimeConfig: {
    public: {
      tide: {
        menuEndpoint: 'linkset'
        ...