[SUGGESTION] Add deprecated networks with flag

[GabrielCartier]

Problem Statement

Some networks that are deprecated are not in the list. However, these networks are still needed for legacy reasons in substreams applications. Currently, there's no way to access information about these deprecated networks through the registry.

Proposed Solution

Add deprecated networks to the registry with a deprecated flag to distinguish them from active networks.

Registry Changes

• Add a deprecated boolean field to network entries
• Include deprecation_reason field (optional) for documentation
• Include deprecated_date field for tracking

This would allow the registry to contain both active and deprecated networks, with clear marking of their status.

Implementation Notes

The registry would include all networks (active and deprecated). Libraries that fetch from this registry could be modified in their respective repositories to filter out deprecated networks by default, with an option to include them when needed.

Benefits

1. Legacy Support: Downstream applications can access deprecated network information when needed
2. Historical Record: Maintains a complete record of all networks that have existed
3. Flexibility: Libraries can choose how to handle deprecated networks based on their needs
4. Documentation: Provides context for why networks were deprecated

Impact

• Registry will be larger as it includes deprecated entries
• Potential breaking changes for people fetching the registry directly and not filtering out the deprecated one. But can be fixed with the next point.
• Libraries consuming this registry may need updates to handle the deprecated flag appropriately

[GabrielCartier]

@maoueh pinging you here.

[p-diogo]

I personally like this. And, btw, the graph-node team started doing something similar in the feature matrix recently: graphprotocol/indexer#1129

[YaroShkvorets]

In the context of substreams, what "deprecated" would mean here? What are the examples of deprecated networks today?

[GabrielCartier]

In the context of substreams, what "deprecated" would mean here? What are the examples of deprecated networks today?

For example, eth goerli and eth Mumbai. Both these networks are deprecated but we still got data on them and would like to be able to allow users to filter through them. That's for the frontend of course.

[YaroShkvorets]

Added to the list for the next schema update: #56