commands index data model refinement

[AlexRuiz7]

Description

Related issue: wazuh/wazuh-indexer#349

We have refined the index data model for the commands index. We need to update the index definition and the index template in the Command Manager plugin with the following changes:

• Add agents.group.
• The command.target field becomes an object with the following fields:
  • command.target.type, replacing command.type.
  • command.target.id, replacing command.target.
• command.action.type is renamed to command.action.name

See #42 (comment)