[Deliverable] Introduce Waku API in nwaku

[Ivansete-status]

Owner: nwaku

Feature: Waku SDK

FURPS:

• F1. Setup, start and stop a Waku node.
• F3. Support relay node operation mode.
• F4. Does automatic peer discovery based on the node platform and operation mode.
• F5. Returns health and connectivity information using proven heuristics.
• F6. Previously discovered peers are persisted across restarted, and potentially used for future connections.
• U1. When setting up a Waku node, no need to specify what protocols to mount, only an operational mode (edge or relay).
• U2. Disconnection detection and recovery, and other peer management matters are automatically handled.
• U3. Developers do not need to specify the protocols used to send and receive messages; it is deduced from the mode of operation.
• U4. Developers pass and receive data to the API in types native to the wrapping language.
• U5. By default, auto-sharding is applied, meaning developers do not need to be concerned by sharding; pubsub topics are never exposed.
• U6. Developers only need to handle errors in cases of irretrievable failure requiring end-user action. Internal errors are not bubbled up if they can be recovered internally.
• R1. Sends a message using peer-to-peer reliability (service node redundancy, optional store confirmation)
• R2. Receives messages using peer-to-peer reliability (service node redundancy, periodic store query, periodic filter ping)

For:

• S1. Nim library; import via git path.
• S2. Golang library; available on pkg.go.dev.

Checklist:

• Specs: Define Waku API specs#68
• Code: link to GitHub issues/PRs/Epic
• Dogfood: link to dogfooding session/artefact
• Docs: links to README.md or docs.waku.org (TBD)