Split ENSNode metadata into ENSNode configuration and ENSNode indexing

[tk-o]

We might want to separate the API endpoint for getting the latest indexing status from the API endpoint that gets the whole configuration of an ENSIndexer instance. Because the configuration of an ENSIndexer instance should generally not be changing every second, whereas the latest indexing status can be changing super fast. So we want to make it comfortable to smash the indexing status endpoint very frequently for live state.

Assume for example that 20 people are refreshing the indexing status dashboard every second. Our code should be implemented such that this requires very little work in ENSIndexer.

[tk-o]

Suggested changes

/metadata endpoint might be removed and instead split into two separate APIs:

1. /config that returns a "public" version of an ENSIndexer config object. This API should have no added complexity or abstractions that try to make it generalizable to any Ponder app. It should be 100% just for ENSIndexer. Please see a related issue for a "private" / "internal" version of an ENSIndexer config object that would include "private" details such as database connection strings, etc.. that we would want to remove from the "public" version of the config object.
2. /indexing-status that returns details including:

• Which chains are being indexed.
• For each of those chains:
  • Block ranges being indexed.
    • Please see the related comments on PR 494 that @oneofthemanymatts
      is working on. See Comment 1 & Comment 2
  • Last indexed block (only if network is currently being indexed, which might not always be the case)
  • Latest safe block
• Indexing mode that is activated. Ex: multichain vs omnichain.
• (whatever else is important for showing live indexing status)

[tk-o]

Will be resolved when all of the following PRs are merged:

• feat(ensnode-sdk): shared validations #894
• feat(ensindexer): /api/config API endpoint #895
• feat(ensindexer): /api/indexing-status API endpoint #896

Those PRs define required data models for ENSIndexerPublicConfig and ENSIndexerIndexingStatus, and with these models, new API endpoints are introduced:

• /api/config
• /api/indexing-status

[tk-o]

All related PRs have been merged, this issue is completed now.