Improvement: Add tracing for subscription-states

### What

The following proxy side trace-points (see `score/mw/com/impl/tracing/configuration/comtrace_config_schema.json`) are currently not yet implemented:

- trace_subscription_state_changed
- trace_subscription_state_change_handler_registered
- trace_subscription_state_change_handler_deregistered
- trace_subscription_state_change_handler_callback

the underlying API entry-points all exists/are implemented, so no reason, not to implement these trace-points.

### How

All these trace-points can now be implemented.
`trace_subscription_state_changed` and `trace_subscription_state_change_handler_callback` shall (additiojnally to the stadard meta-info) provide as - chunk list: value new subscription state (8 bit value)

### Estimates for realization

2 weeks

### Category

- [ ] Affects Detailed Design

### Requirements / Architecture

- [x] Requirements / Architecture are not affected by this change?