Document if a setting can be edited in APM Central Management and add more settings in agents

**Is your feature request related to a problem? Please describe.**

Not specifically a problem, but it would be great to outline in the Documentation of the APM Agents which are the settings which are not only dynamic, but editable with APM Central Management in Kibana.

**Describe the solution you'd like**

1. Add a marker/flag in the documentation of all APM Agents to tell if the setting is not only dynamic but editable with APM Central Management in Kibana.
2. Add more dynamic settings to APM Agents

**Describe alternatives you've considered**

N/A

**Additional context**

Having more dynamic and editable settings without restarts of the application is crucial in production environments.