Introduce a JSON file into the personal data export.

[xkon]

There have been discussions for supporting a JSON format as well for a long time now (including the cross-privacy group) but it was never implemented or was skipped for other priorities.

I think it would be a +1 if we could introduce this in 5.4.

The patch creates an "export.json" that will be compressed in the produced zip along with the current index.html.

I've reorganized the code on the exporter a bit as well so we can benefit from 1 data group going into 2 different files as needed.

This was also mentioned as an extra request in #46424.

[xkon]

I missed adding the $json_report_pathname to the wp_privacy_personal_data_export_file_created action on the previous patch.

49029.2.diff​ appends the extra pathname at the end of the action to avoid breaking any possible existing calls.

[xkon]

49029.3.diff​ adds phpunit tests as well for the JSON file.

I've tested again all default exports, as well as content from extra plugins and everything, seems to be working as expected.

Marking this for commit.

[SergeyBiryukov]

In 47146:

Privacy: Introduce a JSON file into the personal data export.

The produced ZIP archive will now include an export.json file along with the current index.html.

Props xkon.
Fixes #49029. See #46424.

[xkon]

Sorry @SergeyBiryukov ! Reopening this for a missed doc on the created file action.

49029.4.diff​ takes care of that also 😅.

[SergeyBiryukov]

In 47150:

Docs: Document the addition of $json_report_pathname parameter to the wp_privacy_personal_data_export_file_created action.

Follow-up to [47146].

Props xkon.
Fixes #49029.

[garrett-eclipse]

Dev Note: ​https://make.wordpress.org/core/2020/03/02/privacy-updates-in-5-4/

[garrett-eclipse]

Dropping privacy focus as it's already in the Privacy component.