Update DocSearch from v2 to v3

[adriendupuis]

Question	Answer
JIRA Ticket	N/A
Versions	All

From docsearch 2.6.3 to @docsearch/js 3.0.0 https://docsearch.algolia.com/docs/migrating-from-v2

Preview: https://ez-systems-developer-documentation--1592.com.readthedocs.build/en/1592/

Migration doc is kind of wrong: container doesn't work like inputSelector

• https://docsearch.algolia.com/docs/api#container
• https://docsearch.algolia.com/docs/legacy/dropdown

TODO:

• [ ] Styling