Add API Search to Apigee D8 Kick Start

[RaymonLPeng]

Is your feature request related to a problem? Please describe.
Add a site search feature to the Apigee D8 Kick Start bundle and add it to the demo site: http://dev-kickstart-d8.devportal.apigee.io/

Describe the solution you'd like
Add a "Im looking for..." search box, see example on RBC Dev Portal Site:
https://developer.rbc.com/ with basic search results/

The search should cover both API Product/Specs and other pages like Getting Started, FAQ, blog. It would be ok if the blog or forum was excluded as the primary use case is to find a API.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Our customers typically will load 100s of APIs if not 1000s of APIs into the Dev Portal. Browsing is not an effective way to find APIs. Also customer expect google to provide great search tool. I would highly suggest to make sure the search works very well and is able to find all APIs on the Dev Portal

[shadcn]

@RaymonLPeng API product is being converted to Content entities. See apigee/apigee-api-catalog-drupal#71

This means we will have out of the box support for search once this is done.

If you need a solution meanwhile, I created a PR here that replaces the default search with search_api with both Content and API support.

You could apply this PR as a patch.

1. Install composer-patches:

composer require cweagans/composer-patches

2. Add the following under extra in your root composer.json file:

    "patches": {
      "apigee/apigee_devportal_kickstart": {
        "Add content and API search": "https://patch-diff.githubusercontent.com/raw/apigee/apigee-devportal-kickstart-drupal/pull/361.patch"
      }
    },

3. Apply the patch.

composer install

4. Enable the apigee_kickstart_search module.

Clear your cache and you should be ready to go.

When we release support for API search, you should be able to safely uninstall the module and remove the patch from your composer.json file.