Agent group takes a long time to attach to agent heartbeat

[manrodrigues]

When a group is created with tags matching the agent, the agent should be instantaneously reloaded and the group must be attached to them.

Steps to reproduce:

1. Provide an agent with tags
2. Create a group with same tag as agent
3. Check agent's heartbeat on API
4. Check agent view page

Expected result: Group must be attached to the agent quickly

Current result: Group takes almost a minute to be attached to the agent. This time can sounds as a "fail to subscribe" for the users

Scenario: Agent subscription to group after editing orb agent's tags (agent provisioned before editing and group created after) I have put more time to wait on this scenario, just to avoid fail information.. but we need to improve this. It is very intermittent.

[manrodrigues]

Same thing occurs when some dataset is invalidated.. the change takes a long time to reflect as applied.

[manrodrigues]

When some group linked to a group is removed, it takes a "long" time to reflect the updates as well.