[WEB-5246] Typesense UI Adapter (Docs site)

[DavidWeid]

What does this PR do? What is the motivation?

• Adds typesense instantsearch adapter package and replaces algolia with it in instantsearch.js (formerly algolia.js)
• Renames all algolia files and instances used in front end search UI with typesense or instantsearch

Jira Ticket

https://datadoghq.atlassian.net/browse/WEB-5246

Todo

• Update additionalSearchParameters with real query_by value
• Update indexName to api_index once that collection has been created in Typesense
• Replace searchFunction with onStateChange (non-blocking, instantSearch-related updated)

Preview

Review all aspects of search (homepage, search results page, regular pages in the side nav, mobile nav search bar: https://docs-staging.datadoghq.com/davidweid/typesense-ui-adapter/

Merge instructions

• [ ] Please merge after reviewing

Additional notes

https://datadoghq.atlassian.net/browse/WEB-5246