[Ingest Manager] Follow up on data_stream and policy renaming

[ruflin]

It was decide that dataset is renamed to data_stream and config to policy. Many changes related to it have already been merged. But there still a few missing bits. This issue is to collect and track the changes needed on the Kibana side:

• Rename files, client routes, api routes, variables, comments, etc everywhere in code from agent/package config/s -> agent/package policy/ies [Ingest Manager] Rename agent/package config(s) to agent/package policy(ies) #74914
  • Add SO migrations for SO attribute renaming
• Update UI copy [Ingest Manager] Rename agent/package config(s) to agent/package policy(ies) #74914
• Rename (most) mention of dataset to data stream. Note: data_stream.dataset still exists, in some places it will still be used [Ingest Manager] Update "datasets" UI copy to "data streams" #75618
• Rename CONFIG_CHANGE action type to POLICY_CHANGE [Fleet] Rename CONFIG_CHANGE action to POLICY_CHANGE #78221
• Follow package spec changes [Ingest Manager] Match package spec dataset->data_stream and config_templates->policy_templates renaming #78699
  • For data_stream: [Discuss] Impact of renaming dataset to data_stream package-spec#18
  • For policy: [Discuss] Impact of renaming config to policy package-spec#19
  • Figure out migration path from 7.9 to 7.10
• File issue to update docs: [Fleet] Rename agent config references to agent policy, and datasets to data streams observability-docs#164

In case the package spec changes, it will probably mean we need to migrate some internal structures over to 7.10 to make sure things still work.

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[jen-huang]

@ruflin Going to close this issue as done:

1. [Ingest Manager] Match package spec dataset->data_stream and config_templates->policy_templates renaming #78699 has been merged and tested with package changes
2. [Fleet] Rename agent config references to agent policy, and datasets to data streams observability-docs#164 filed to update public docs, the above PR also contained changes to dev docs
3. WRT Figure out migration path from 7.9 to 7.10, I don't think there is any further work needed here since 7.9 is using a different EPR CNAME. The Kibana PR didn't have any kind of changes that would need any migrations.