Review use of deprecated apm settings (#2274)

tracing.apm.* settings were deprecated in 8.14.0 in favor of the new
telemetry.* settings. Use the new settings starting with 8.14.0.

Old settings will be removed in 9.0.

Settings have been also reviewed for older versions of the stack.

Author: jsoriano

internal/stack/_static/elasticsearch.yml.tmpl

@@ -28,8 +28,14 @@ script.context.template.cache_max_size: 2000
 {{- end -}}
 
 {{ $apm_enabled := fact "apm_enabled" }}
-{{ if eq $apm_enabled "true" }}
+{{ if (and (eq $apm_enabled "true") (not (semverLessThan $version "8.5.0"))) }}
+{{ if semverLessThan $version "8.14.0" }}
 tracing.apm.enabled: true
 tracing.apm.agent.server_url: "http://fleet-server:8200"
 tracing.apm.agent.environment: "dev"
+{{- else -}}
+telemetry.tracing.enabled: true
+telemetry.agent.server_url: "http://fleet-server:8200"
+telemetry.agent.environment: "dev"
+{{- end -}}
 {{- end -}}

internal/stack/_static/kibana.yml.tmpl

@@ -101,7 +101,9 @@ xpack.fleet.agentPolicies:
             vars:
               - name: custom
                 value: |
+      {{ if not (semverLessThan $version "8.8.0") }}
                   server:
+      {{ end }}
                     instrumentation:
                       enabled: true
                       hosts: ["http://fleet-server:8200"]