feat(telemetry): add metrics for query plan warmup and schema loading

[bnjjj]

It adds histogram metrics for apollo_router_query_planning_warmup_duration and apollo_router_schema_load_duration.

Example in Prometheus:

# HELP apollo_router_query_planning_warmup_duration apollo_router_query_planning_warmup_duration
# TYPE apollo_router_query_planning_warmup_duration histogram
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.05"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.1"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.25"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.5"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="1"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="2.5"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="5"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="10"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="20"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="100"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="1000"} 1
apollo_router_query_planning_warmup_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="+Inf"} 1
apollo_router_query_planning_warmup_duration_sum{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version=""} 0.022390619
apollo_router_query_planning_warmup_duration_count{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version=""} 1
# HELP apollo_router_schema_load_duration apollo_router_schema_load_duration
# TYPE apollo_router_schema_load_duration histogram
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.05"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.1"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.25"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="0.5"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="1"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="2.5"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="5"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="10"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="20"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="100"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="1000"} 8
apollo_router_schema_load_duration_bucket{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version="",le="+Inf"} 8
apollo_router_schema_load_duration_sum{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version=""} 0.023486205999999996
apollo_router_schema_load_duration_count{service_name="apollo-router",otel_scope_name="apollo/router",otel_scope_version=""} 8

Fixes #3767

Checklist

Complete the checklist (and note appropriate exceptions) before a final PR is raised.

• Changes are compatible[^1]
• Documentation[^2] completed
• Performance impact assessed and acceptable
• Tests added and passing[^3]
  • Unit Tests
  • Integration Tests
  • Manual Tests

Exceptions

Note any exceptions here

Notes

[^1]. It may be appropriate to bring upcoming changes to the attention of other (impacted) groups. Please endeavour to do this before seeking PR approval. The mechanism for doing this will vary considerably, so use your judgement as to how and when to do this.
[^2]. Configuration is an important part of many changes. Where applicable please try to document configuration examples.
[^3]. Tick whichever testing boxes are applicable. If you are adding Manual Tests:
- please document the manual testing (extensively) in the Exceptions.
- please raise a separate issue to automate the test and label it (or ask for it to be labeled) as manual test

These are existing metrics

[BrynCooke]

Metrics need to be in otel style and not prom style.
These are new metrics and must be checked for consistency with other new metrics.

[BrynCooke]

The new metrics namespaces will also need to be added to the apollo metrics filter.