fix: Add http path prefix as metrics labels

[nssherpa]

Testing

Currently we don't have enough visibility into what is being called. This adds a cachew.http.path.prefix label.

 curl -s http://localhost:9102/metrics | grep 'cachew_path_prefix=' | sed 's/.*cachew_path_prefix="\([^"]*\).*/\1/' | sort -u
_readiness
git
github.com
hermit

http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="1000"} 1
http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="2500"} 1
http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="5000"} 1
http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="7500"} 1
http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="10000"} 1
http_server_duration_milliseconds_bucket{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0",le="+Inf"} 1
http_server_duration_milliseconds_sum{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0"} 15.430042
http_server_duration_milliseconds_count{cachew_path_prefix="hermit",http_method="GET",http_scheme="http",http_status_code="200",net_host_name="localhost",net_host_port="8080",net_protocol_name="http",net_protocol_version="1.1",otel_scope_name="go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",otel_scope_version="0.58.0"} 1
# HELP http_server_request_size_bytes_total Measures the size of HTTP request messages.
# TYPE http_server_request_size_bytes_total counter