feat: improve reuse of pubsub/content topic configuration

[adklempner]

This is a bug report/feature or change request/support request

Problem

The library consumer has to set the content/pubsub topic in multiple places:

• when creating the waku node
• when creating an encoder/decoder
• when creating a subscription

If the three don't match, then it can lead to unwanted behaviour

Proposed Solutions

Notes

[danisharora099]

issue description is empty. moving this back to triage

[weboko]

@adklempner could you, please, provide description and some examples of what this feature is about. If possible - link it to relevant epic or milestone

[weboko]

Moving to priority as it is better to finalize before the next release.

[danisharora099]

@weboko are we set on the proposed solution? do we want to triage it before we tackle it?

[weboko]

Proposed solution:

• drop pubsubTopic;
• combine shardInfo and contentTopics under new property network or networkConfiguration;
• add default export of TWN shardParams from @waku/*package and make them default in case defaultBootstrap is used;
• add createEncoder and createDecoder as part of WakuNode to be used as follows:

const node = createLightNode({ defaultBootstrap: true });
const encoder = node.createEncoder({ ... }); // <- potentially by using some params asym/sym encoder/decoder can be instantiated
const decoder = node.createDecoder({ ... });

• creating subscription should be improved as part of and as per specified solution in feat: use decoder as a seed for subscription #2034;