[pkg/inframetadata] Improve warning when host-identifying attributes are missing

[mx-psi]

What does this PR do?

Uses AsRaw for printing resource attributes and links reference page on mapping OTLP resource attributes to hostnames.

Motivation

pcommon.Map doesn't have a very sensible formatting. With the following sample program:

package main

import (
	"go.opentelemetry.io/collector/pdata/pcommon"
	"go.uber.org/zap"
)

func main() {
	logger := zap.NewExample() // or NewProduction, or NewDevelopment
	defer logger.Sync()

	m := pcommon.NewMap()
	if err := m.FromRaw(map[string]any{"key": "value"}); err != nil {
		panic(err)
	}

	logger.Info("Testing logging of pcommon.Map", zap.Any("map", m), zap.Any("raw map", m.AsRaw()))
}

We can see the following output:

❯ go run main.go
{"level":"info","msg":"Testing logging of pcommon.Map","map":{},"raw map":{"key":"value"}}

Where map is shown as empty, when it isn't. Casting to a map with AsRaw fixes the issue