feat: lightPush v3

[weboko]

Description

Following nwaku we are ready to implement LightPush v3 protocol in js-waku.

User Story

• As js-waku consumer I want to use one LightPush send API, so that my applications are simple.
• As Waku CC I want to move all implementations to one, unified LightPush version, so that we don't introduce significant breaking changes;
• As Waku CC I want to ensure that js-waku works with both old and new LightPush, so that consumers can operate on one network;
• As LightPush user I want to know when and with what error request failed, so that I can better react to this;

Proposed Solution / Feature Design

We need to implement LightPush v3 core protocol similarly to how v2 exists AND consumer it in LightPush SDK in a smart way.

Clarifications:

1. Implement v3 as another core protocol along v2 that is in use now.
2. Ensure that LightPush returns proper error codes as defined in the specification.
3. Ensure LightPush SDK is smart and uses LightPush v3 when a peer implements it (based on advertised protocols) or LightPush v2 otherwise - here.

Notes

• Spec - https://github.com/waku-org/specs/blob/master/standards/core/lightpush.md
• nwaku protocol handler - https://github.com/waku-org/nwaku/blob/master/waku/waku_lightpush/protocol.nim
• nwaku lightPush client - https://github.com/waku-org/nwaku/blob/master/waku/waku_lightpush/client.nim