fix: Make service name configurable for Metrics and Tracing (#9563)

# Which Problems Are Solved

The service name is hardcoded in the metrics code. Making the service
name to be configurable helps when running multiple instances of
Zitadel.

The defaults remain unchanged, the service name will be defaulted to
ZITADEL.

# How the Problems Are Solved

Add a config option to override the name in defaults.yaml and pass it
down to the corresponding metrics or tracing module (google or otel)

# Additional Changes
NA

# Additional Context
NA

(cherry picked from commit dc64e35128)

cmd/defaults.yaml

@@ -14,6 +14,7 @@ Tracing:
   # for type 'otel' is used for standard [open telemetry](https://opentelemetry.io)
   # Fraction: 1.0
   # Endpoint: 'otel.collector.endpoint'
+  # ServiceName: 'ZITADEL' # Name of the service in traces
   #
   # type 'log' or '' disables tracing
   #
@@ -24,6 +25,8 @@ Tracing:
   Fraction: 1.0 # ZITADEL_TRACING_FRACTION
   # The endpoint of the otel collector endpoint
   Endpoint: "" #ZITADEL_TRACING_ENDPOINT
+  # The name of the service in traces
+  ServiceName: "ZITADEL" #ZITADEL_TRACING_SERVICENAME
 
 # Profiler enables capturing profiling data (CPU, Memory, ...) for performance analysis
 Profiler: