As of elastic/elasticsearch#108860
(due to be released in 8.15.0), the apm-data Elasticsearch
plugin is enabled by default and will take care of installing
index templates and ingest pipelines for APM; the integration
package no longer needs to (nor should) install its own.

With this change, the integration package is optional for APM:
it is still useful for running with Fleet, but otherwise users
may rely on templates/pipelines being set up by Elasticsearch.