Add support for store mapping property

[jsoriano]

What does this PR do?

Add support for the store mapping option.

Why is it important?

When synthetic mode is used, there are some cases where we may need to ensure that some fields are stored. See for example https://github.com/elastic/integrations/pull/9826.

Checklist

• [x] I have added test packages to test/packages that prove my change is effective.
• [x] I have added an entry in spec/changelog.yml.

Related issues

• Needed for uses cases like https://github.com/elastic/integrations/pull/9826 in recent versions of the spec.

[jsoriano]

This change is not enough, this needs to be supported by Fleet, I will move the change to 3.2.0.

[elasticmachine]

:green_heart: Build Succeeded

• Buildkite Build
• Commit: 46ea475e841663e231f067c0e9c0bba0c9efa8b0

History

• :green_heart: Build #651 succeeded d0f1a9738687d95e1ab8b971848a098884d41c8a
• :green_heart: Build #650 succeeded 4555db9cbe84fdc2d77b2a4d7aa978e41c1d4acc
• :green_heart: Build #649 succeeded 572641c5e75c6f2bdfabe050abf0d18a2525650a

cc @jsoriano