Provide a top level search for Rarible protocol APIs

[bobwith2bees]

Ask:
Searching for the various API endpoints requires multiple searches across each of the OpenAPIs within the Rarible protocol project. This leads to confusion when you cannot quickly find out which API has the features you are looking for.

Priority: "Would be nice" (Low, but if you want to grow the protocol adoption this is a pain point....)

Justification:
I was looking at the API reference from the top level page which is not the same as the API reference for ethereum
docs.rarible.org > API Reference > Mainnet

• https://docs.rarible.org/api-reference/
  docs.rarible.org > Ethereum Overview > API Reference > Mainnet
  The other protocols have similar API Reference pages
• https://docs.rarible.org/ethereum/ethereum-overview/#api-reference
  docs.rarible.org > API Reference > Tezos Overview > API Reference
  https://docs.rarible.org/tezos/tezos-overview/#api-reference
  docs.rarible.org > API Reference > Flow Overview > API Reference
  https://docs.rarible.org/flow/flow-overview/#api-reference

NOTE: The search box in the upper left hand corner only searches that specific OpenAPI tree. So I was searching for generateNftTokenId on the wrong API and thought it was deprecated when I didn't find it. I am looking for a solution that could search all the APIs, then direct me to the correct one.