[Request] Create APM integration documentation

[bmorelli25]

Description

Create a new APM integration documentation book. This book should contain all APM Overview content and a new, legacy section for deprecated content.

7.16

Move old content. Make easy updates. Stop building old docs.

• Move deprecated documentation to a legacy directory
  • docs: APM integration documentation apm-server#6287
• Add the APM User Guide to the doc build (incl attrs)
  • Add APM Guide docs#2246
  • Build 7.x branch of APM Guide docs#2250
• Move APM Overview content to the APM guide
  • Add content to APM User guide apm-server#6378
• Move APM Server Reference content to the APM guide
  • Add content to APM User guide apm-server#6378
  • docs: add release notes, API, and auth docs to APM Guide apm-server#6427
• Duplicate Stack Overview includes to APM User Guide
  • docs: link to new APM book stack-docs#1850
• Open PRs to fix all broken links (list) Stop building APM Server and Overview books docs#2239 (comment)
  • docs: link to new APM book beats#28519
  • docs: link to new APM book stack-docs#1850
  • [DOCS] Temporarily remove APM links elasticsearch#79411
  • docs: update APM links #1181
  • docs: Fix hard-coded APM link kibana#115642
  • docs: update links to APM docs kibana#115664
  • docs: fix link ecs#1631
  • Update links to APM docs kibana#116529
  • docs: fix links and remove temp files apm-server#6477
• Stop building the APM Server Reference and APM Overview
  • Stop building APM Server and Overview books docs#2239
• Simulate bump to 7.16 (with an elastic/docs PR) and open issues to fix all broken APM agent links: APM: simulate bump to 7.16 docs#2276
  • Go [Go agent] Update APM language and links #1214
  • iOS [iOS agent] Update APM language and links #1222
  • Java [Java agent] Update APM language and links #1216
  • .NET [.NET agent] Update APM language and links #1215
  • Node.js [Node.js agent] Update APM language and links #1217
  • PHP [PHP agent] Update APM language and links #1218
  • Python [Python agent] Update APM language and links #1219
  • Ruby [Ruby agent] Update APM language and links #1220
  • RUM [RUM agent] Update APM language and links #1221

Additional content improvements

• [APM] Document data streams #1223
• [APM] Document ILM policies and how to override them #1224
• [APM] Update input settings names #1225
  - [ ] [APM] Document custom ingest pipelines #1226 Moved to 8.0
  - [ ] [APM] Update terminology #1227 Moved to 8.0
  - [ ] [APM] Update data security pipeline example #1228 Moved to 8.0
• [APM] Fix broken pages in legacy docs #1229
• Add deprecation notice to source map upload docs, redirect to Kibana API apm-server#6433
• Deprecate apm_system user #1213 Moved to a future iteration
• [APM] Update quick start guides #1231
• Remove all temp files
• Remove old ES ifeval https://github.com/elastic/elasticsearch/blame/master/docs/Versions.asciidoc#L72 docs: remove old APM ifeval  elasticsearch#81402
• Fix broken obs docs includes
• Request redirects for APM Server Reference and APM Overview master, 8.0, and 7.16
  • https://github.com/elastic/website-development/issues/8388
• Add deprecation notices to legacy docs: docs: Add "deprecating soon" notices apm-server#6708
• Add upgrading guide docs: Add upgrading documentation apm-server#6709
• Move APM Server Reference and APM Overview to Legacy docs Move APM Reference and Overview to Legacy section docs#2309
• Add banner to 7.15 docs [7.15] Add page header to legacy docs apm-server#6833

After release

• Fix link to APM Guide in the ECS docs: docs: fix link to APM Overview ecs#1710
• [APM] Update hard-coded links to Go Agent #1285

If I have time

- [ ] #1288 Moved to 8.0

Suggested Target Release

7.16

Stakeholders

@simitt @bmorelli25

[bmorelli25]

To do: Establish the term instrumentation libraries when describing apm agents, and the term collector when describing the APM integration (APM Server). These terms will not replace the established Elastic terminology.