Add Documentation for Public Universe Server and Endpoints

[ffranr]

We need to enhance the Universes documentation by adding a new section dedicated to Public Universe Servers.

Content to consider

1. Introduce Public Universe Server:

   • Provide a clear and detailed description of what a public universe server is in the context of Taproot Assets.
   • Explain its role and purpose within the tap ecosystem.
   • Explain how some organizations may run a limited public universe server that might only recognize a limited set of tap assets.
   • Explain the role of a public universe server in proof transfers for tap asset transfers.

2. Document RPC/REST Endpoints:

   • List and describe the RPC/REST endpoints available on a public universe server that developers can utilize.
   • Include direct links to the relevant endpoints in the API documentation, specifically from the Universe Service Endpoints.
     • For example, link to the InsertProof endpoint and provide a brief overview of its functionality.

3. Clarify Macaroon Authentication:

   • Explain that while the API documentation may indicate that a macaroon is required for authentication, the public universe server endpoints actually ignore the macaroon if provided.

[ZZiigguurraatt]

Found some definition of the public endpoints here: https://github.com/Roasbeef/bips/blob/bip-tap/bip-tap-universe.mediawiki#universe-grpc-api . The reference comes from here:

docs.lightning.engineering/the-lightning-network/taproot-assets/taproot-assets-protocol.md

Line 177 in 0ba7c3c

[Read the BIPs: Taproot Asset Universes](https://github.com/Roasbeef/bips/blob/bip-tap/bip-tap-universe.mediawiki)

.

[Liongrass]

I made edits to this guide, have a look if this is satisfactory:
https://docs.lightning.engineering/lightning-network-tools/taproot-assets/universes

[ZZiigguurraatt]

I made some comments: a2edb81#comments .

[ZZiigguurraatt]

Here is a list of the public REST endpoints

https://github.com/Roasbeef/bips/blob/bip-tap/bip-tap-universe.mediawiki#universe-rest-api

Is there any way we can label each endpoint on https://lightning.engineering/api-docs/category/universe-service/index.html to say if it is a public or private one?

[Liongrass]

Thank you very much for that! I've addressed your points in this change:
c3609e3