Rename changes and validation fixes

[jonathan-buttner]

This PR renames the dataset directories under the package to data_stream and config_templates to policy_templates in the manifest.yml file.

This PR needs to be coordinated with elastic/kibana#78699

The easiest way to review this PR is commit by commit. Here's what each commit does:

• Making validation changes and new elastic-package
  • Does the dataset to data_stream directory change
  • config_templates change
  • Updates the go files to a newer elastic-package tool
• renaming fields and using new elastic-package linter
  • Changes the format of the index_template.mappings to the expanded format because the package spec validator doesn't support both formats right now, it's only the expanded object style
  • fixes the makefile paths to use data_stream
  • renames the dataset references in the scripts
  • applies the latest formatters rules for indentation
• Pulling in the new elastic-package for linting and validation
  • Pulls in the latest elastic-package tool with the histogram field fix so the endpoint package doesn't fail validation
  • switches the ECS directory target so it required when setting up the repo's tools
• Adding in lint to make command
  • Adds the elastic-package lint command during the make process to ensure that the package is still valid

References:
https://github.com/elastic/integrations-dev/issues/162

• Dataset to data stream package-spec#24
  • datasets->data_streams property
  • datasets.name->data_streams.dataset property
  • /dataset->/data_stream directory
• Rename config to policy package-spec#50
  • config_templates->policy_templates property

[michaelolo24]

This doesn't need to be the expanded format?

[jonathan-buttner]

No it has to be in the dot format for now. The spec on supports one or the other and currently it needs the dot format for that field: https://github.com/elastic/package-spec/blob/master/versions/1/manifest.spec.yml#L97