feat(msd): adding timestamp of last successful sync

[NikolaMilosa]

Example of the metric:

# HELP http_server_active_requests The number of active HTTP requests.
# TYPE http_server_active_requests gauge
http_server_active_requests{http_request_method="GET",url_scheme="http",otel_scope_name="axum-app"} 1
# HELP msd_definitions_load_errors Total number of errors while loading new targets per definition
# TYPE msd_definitions_load_errors gauge
msd_definitions_load_errors{network="mercury",otel_scope_name="axum-app"} 0
# HELP msd_definitions_load_successful Status of last load of the registry per definition
# TYPE msd_definitions_load_successful gauge
msd_definitions_load_successful{network="mercury",otel_scope_name="axum-app"} 1
# HELP msd_definitions_sync_errors Total number of errors while syncing the registry per definition
# TYPE msd_definitions_sync_errors gauge
msd_definitions_sync_errors{network="mercury",otel_scope_name="axum-app"} 0
# HELP msd_definitions_sync_successful Status of last sync of the registry with NNS of definition
# TYPE msd_definitions_sync_successful gauge
msd_definitions_sync_successful{network="mercury",otel_scope_name="axum-app"} 1
# HELP msd_definitions_sync_ts Timestamp of last successful sync
# TYPE msd_definitions_sync_ts gauge
msd_definitions_sync_ts{network="mercury",otel_scope_name="axum-app"} 1718637276
# HELP target_info Target metadata
# TYPE target_info gauge
target_info{service_name="unknown_service",telemetry_sdk_language="rust",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="0.22.1"} 1

[sasa-tomic]

🚀 TY!