Support to add any Squid to the .env file

[sacha-l]

For someone who wants to use Uniquery with any valid chain, it would be awesome to be able to pass in a valid Squid data source in the .env file and to be able to use Uniquery on it (so long as they have a valid indexer for it of course).

There are many existing archives hosted by Subsquid. In my case for example, I would like to use the Statemine archive as my data source (https://statemine.archive.subsquid.io/graphql) in a fork of the Fandom app.

How would we be able to add functionality to Uniquery in order to achieve this?

For example, in the .env file here, we could do:

ADDRESS=JHfxh28HRxd5fSY97fFoPfFXHmGGFGctNNr9GvmnNeQPVkS
CHAIN=https://statemine.archive.subsquid.io/graphql

I notice it's to do with creating an additional field as a SquidEndpoint (like you do here in the NFT Gallery). But I'm not sure how to do this for Uniquery. If you can provide the steps and mentor a little, I'd love to learn how to do this. 🙏🏻 🌈