SPIKE - PoC implementation for agent and server

[Selutario]

Description

We are refactoring the way wazuh agents and servers communicate as part of #22677. In this issue, we must develop a proof of concept where the designs proposed in the two issues below are put into practice.

• SPIKE - New Agent comms API endpoint client wazuh-agent#1
• SPIKE - Initial Agent comms API server design #23395

Both communication modes (event-driven and session-oriented) should work between the agent and the server upon completion of this PoC. This involves the implementation of a stateless endpoint and another session-type endpoint, specifically, /commands. The command manager will be handled by the indexer in the future. In the meantime, as part of this PoC, it should be mocked.