Move index templates and ingest pipelines from apm package to ES

[simitt]

Add index templates and ingest pipelines, currently defined in the apm-package, to Elasticsearch itself.

See a proof of concept at elastic/elasticsearch#97546. Thus, by default, APM could index into a fresh Elasticsearch cluster without any checks that the templates and pipelines are set up.

[axw]

After elastic/elasticsearch#97546 is merged, we'll need to follow up by extending the YAML REST tests (see https://github.com/elastic/elasticsearch/blob/d832ac65b3cd072263dc198fd211f7f87787ec9b/x-pack/plugin/apm-data/src/yamlRestTest/resources/rest-api-spec/test/10_apm.yml), and fix/enhance index templates and ingest pipelines accordingly. These tests should index some sample documents and asserting that they're processed and mapped as expected.

[axw]

With #12066, and the changes in elastic/elasticsearch#103032, I'm able to get all APM Server system tests to pass. There will be some differences to approvals: there are additional .text subfields, and we're not removing fields from span documents like we do in the integration's ingest pipeline. I think both of those changes are desirable.