Add UX in the Network Admin for exporting/anonymizing/deleting personal data across the entire network

[coreymckrill]

It's not practical for a super admin to hunt down personal data by going to the Dashboard of each site in the network. There should be one centralized place in the Network Admin to receive and process SARs.

This should look similar to the UX in #43546 and #43602, but the underlying functionality for managing the data across the entire network is being discussed in #43738.

[iandunn]

I wonder if there are use cases where the network admin will want to delegate this to single site admins. For instance, an agency that has a multisite instance for all of their clients. The sites are completely unrelated to one another, and the individual site admins would be the most appropriate people to respond to SARs, rather than the network admin.

The wp_users table is shared, though, so that's a complication. Maybe v1 just has the network admin doing everything, and future iterations can consider adding granularity?

[iandunn]

Related: r43085

[desrosj]

Moving to the new Privacy component.

[allendav]

The solution will need to take into account mu-plugins / plugins that are used on all the sites vs plugins that are installed on individual sites. The exporters and erasers can vary from site to site.

[desrosj]

Removing the GDPR keyword. This has been replaced by the new Privacy component and privacy focuses in Trac.

[davidbaumwald]

@garrett-eclipse Is this a duplicate of #43738?

Also related #49668

[davidbaumwald]

With 5.5 Beta 1 releasing tomorrow, this is being moved to Future Release. If any maintainer or committer feels the remainder of this ticket can be resolved in time, or wishes to assume ownership during a specific cycle, feel free to update the milestone accordingly.