Replace public archive node

[traumschule]

The archive mentioned in running-local-instance no longer available:

For example, the Joystream mainnet chain has a public archive maintained by Subsquid at https://joystream.archive.subsquid.io/graphql

Update all docs

[traumschule]

Alternatives:

• https://mainnet.joystream.dev/query/indexer/graphql (sunset note)
• https://query.l1.media/indexer/graphql