Improve Chain Index documentation

[kk-hainq]

Area

[x] Plutus Application Framework Related to the Plutus application backend (PAB), emulator, Plutus libraries

Describe the feature you'd like

We should write documentation for chain index setup, API, use cases, customization, and more.

A good start is to add openapi3 support to the RESTful endpoints, similar to IntersectMBO/plutus#3807. We can then write more textual documentation, from high-level guidelines to the details like tuning cicStoreFrom from 2877844 on the testnet, and 6236060 on the mainnet for Alonzo-only transactions, etc.

Describe alternatives you've considered

We mostly infer things from the source code at the moment, which is not always convenient for developers in general.

Additional context / screenshots

This issue is part of the #4 mega-thread.

[Yasuke]

@kk-hainq Thank you for the suggestion, we are making chain-index into a library and we will be documenting the features while doing so.

[kk-hainq]

@Yasuke Awesome, thank you! Let us know if we could help in any way.

[Yasuke]

Hey @kk-hainq It looks like #186 has laid the groundwork for separating chain-index out as a library, if you see anything obviously missing or aren't satisfied with the added documentation, we would definitely appreciate your input into the state of things.

[kk-hainq]

Documentation is hard and dangerous (my left wrist still screams carpal tunnel after our last documentation sprint) so I think we should take steps. We can help add more haddock to plutus-chain-index, plutus-chain-index-core and decorate their README(s) more, what do you think?

[Yasuke]

We would be happy to have your contribution @kk-hainq!

[kk-hainq]

Hang tight my right hand is already typing!

[kk-hainq]

This issue is outdated now. We'll open more documentation issues when it's more appropriate (architecture is finalized, code is refactored well enough, etc.).