feat: HTTP REST API: Filter support v2

[NagyZoltanPeter]

Background

This forms a subtask of #1076 and follow up for #1851
Nwaku nodes operating as 12/WAKU2-FILTER clients can use the filter protocol to subscribe to service nodes to receive messages adhering to a set of subscription criteria.
While #1851 created Rest API interface for the Filter v1 - legacy implementation.
This one should implement new Filter subscription concept available through Rest interface.

Suggested solution

It should follow existing approach with taking care that separate v1 and v2 APIs. For a while they should live together.
Give a concise openapi descriptor.

Acceptance criteria

• working HTTP Filter Client REST API to perform filter client operations on remote service nodes
• sufficient unit tests for basic functionality
• integration of Filter Client API into the wakunode2 app

[NagyZoltanPeter]

Weekly Update

• achieved: PR tracking is feat: HTTP REST API: Filter support v2 #1890
  Review is done, various fixes upon applied
• next: Last, agreed interface change to be done to complete.

[NagyZoltanPeter]

Weekly Update

• achieved: Filter v1 & v2 REST API endpoints merged to master
• next: LightPush REST endpoint