Add appId to Algolia plugin

[jonahtanjz]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• Others, please explain:

Addresses #1729
Overview of changes:
Algolia now requires appId to be provided in order to use its APIs. Add appId to Algolia plugin's options.

Anything you'd like to highlight / discuss:
NIL

Testing instructions:
Add the following to site.json, add algolia attribute to searchbar and serve the site.

"plugins": [
    "algolia"
  ],
  "pluginsContext": {
    "algolia": {
      "apiKey": "599cec31baffa4868cae4e79f180729b",
      "appId": "R2IYF7ETH7",
      "indexName": "docsearch"
    }
  }

Proposed commit message: (wrap lines at 72 characters)
Add appId to Algolia plugin's options

---

Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

[ang-zeyu]

LGTM 👍

[damithc]

@jonahtanjz thanks for tackling this. But it looks like adding appId is not enough to get the module website working for this semester; I should be able to pass in the facetFilters parameter as well. If not, search results will contain results from all of my module websites, not just the target module. This is because Algolia has unified all my search indexes to one (we were given separate indexes for each website before).

[jonahtanjz]

Prof @damithc, try putting the facetFilters in algoliaOptions instead of searchParameters.

"pluginsContext": {
    "algolia": {
      "apiKey": "a3fef7e2d9dea07c0fa2d8ed521057aa",
      "appId": "3DU4XTBX4T",
      "indexName": "nus-tic-cs",
      "algoliaOptions": {
        "facetFilters": ["site:nus-tic2002-2022.github.io"]
      }
    }
  }

[damithc]

Prof @damithc, try putting the facetFilters in algoliaOptions instead of searchParameters.

Ah, that seems to work. Thanks @jonahtanjz