ingest/pipeline: create new data transform interfaces under ingest package

[sreuland]

What problem does your feature solve?

lack of material to guide app developers towards deriving their own data from network data via ingestion.

What would you like to see?

• new package under ingest/pipeline in go sdk to provide a library for application developers to use to build data transformation pipelines based on origin of network data - the tx-meta, aka in stellar xdr model as LedgerCloseMeta. The composition of the library is in draft proposal on CDP Transforms, mainly these structs/types/interfaces:
  • Event
  • Message
  • EventHandler
  • Channels
  • Inbound/Outbound Adapters
  • Processor

What alternatives are there?

[sreuland]

after processors lib design review, we decided to go with a different approach of pipelines created from observable streams using functional operators, this infra not needed and obsoleted by #5412.