cxx/core/heartbeats: provide reason for interrupt

This is a small (but independent) step towards implementing #96. Now the heartbeat manager can provide a reason for interrupting the satellite operation. Right now this is only used for logging, but will later on be useful for setting as a status.

I also changed the log levels of a few things in the FSM because I felt like the same message was repeated several times.

Below are two logs for the same situation, Kronos being terminated from ORBIT state with Aigisthos listening to its heartbeats.

Before:

Satellite Kronos

^C|2024-07-17 15:50:08.646|   STATUS [DEFAULT] Terminating satellite
|2024-07-17 15:50:08.646|   STATUS [FSM] Interrupting...
|2024-07-17 15:50:08.646|     INFO [FSM] Reacting to transition interrupt
|2024-07-17 15:50:08.646|   STATUS [FSM] New state: interrupting
|2024-07-17 15:50:08.646|  WARNING [FSM] Interrupting satellite operation
|2024-07-17 15:50:08.646|     INFO [FSM] Calling interrupting function of satellite...
|2024-07-17 15:50:08.646|     INFO [SATELLITE] Interrupting from ORBIT (default implementation)
|2024-07-17 15:50:08.646|     INFO [FSM] Reacting to transition interrupted
|2024-07-17 15:50:08.646|   STATUS [FSM] New state: SAFE

Satellite Aigisthos

|2024-07-17 15:50:08.694|   STATUS [FSM] Interrupting...
|2024-07-17 15:50:08.694|     INFO [FSM] Reacting to transition interrupt
|2024-07-17 15:50:08.695|   STATUS [FSM] New state: interrupting
|2024-07-17 15:50:08.695|     INFO [FSM] Calling interrupting function of satellite...
|2024-07-17 15:50:08.695|     INFO [SATELLITE] Interrupting from ORBIT (default implementation)
|2024-07-17 15:50:08.695|     INFO [FSM] Reacting to transition interrupted
|2024-07-17 15:50:08.695|  WARNING [FSM] Interrupting satellite operation
|2024-07-17 15:50:08.695|   STATUS [FSM] New state: SAFE

After:

Satellite Kronos

^C|2024-07-17 15:40:08.787|   STATUS [DEFAULT] Terminating satellite
|2024-07-17 15:40:08.787|     INFO [FSM] Reacting to transition interrupt
|2024-07-17 15:40:08.787|   STATUS [FSM] New state: interrupting
|2024-07-17 15:40:08.787|     INFO [FSM] Calling interrupting function of satellite...
|2024-07-17 15:40:08.787|     INFO [SATELLITE] Interrupting from ORBIT (default implementation)
|2024-07-17 15:40:08.787|     INFO [FSM] Reacting to transition interrupted
|2024-07-17 15:40:08.787|  WARNING [FSM] Interrupting satellite operation: Stopping satellite
|2024-07-17 15:40:08.787|   STATUS [FSM] New state: SAFE

Satellite Aigisthos

|2024-07-17 15:40:10.608|     INFO [FSM] Reacting to transition interrupt
|2024-07-17 15:40:10.608|   STATUS [FSM] New state: interrupting
|2024-07-17 15:40:10.608|  WARNING [FSM] Interrupting satellite operation: Sputnik.Kronos reports state SAFE
|2024-07-17 15:40:10.608|     INFO [FSM] Calling interrupting function of satellite...
|2024-07-17 15:40:10.608|     INFO [SATELLITE] Interrupting from ORBIT (default implementation)
|2024-07-17 15:40:10.608|     INFO [FSM] Reacting to transition interrupted
|2024-07-17 15:40:10.608|   STATUS [FSM] New state: SAFE