Add UX in the Network Admin for setting a network-wide privacy policy

[coreymckrill]

Some multisite instances will need to set one privacy policy for the entire network, with controls on whether or not individual sites can modify/replace it. Other multisite instances may choose to leave the privacy policy entirely to individual sites.

The UI for setting a network-wide policy should probably be similar to #43435, so snippets from plugins can be included.

[iandunn]

Related: privacy_policy_url filter proposed in ticket:43620#comment:30.

[iandunn]

Relevant ​feedback from @flixos90 on #43935

I like the capabilities approach, however I think we shouldn’t assume that a network works that way that it has a single privacy policy. I‘d prefer if we introduced an extra setting toggle in the network admin like “Restrict privacy policy management to network administrators?”. Only if that is checked, the capability should be restricted from regular administrators. We could even add a “Use a network-wide privacy policy?” toggle and if that is set, provide a UI in the network admin and then override what’s set per single site, like several other network settings work. The current solution is fine though as first step though, especially since Beta is tomorrow.

[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.

[desrosj]

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 This has been replaced by the new Privacy component and privacy focuses in Trac.

[garrett-eclipse]

This will need a design before feedback can be provided. Switching the keyword ux-feedback for needs-design

[paaljoachim]

Going to My Sites -> Settings shows the following Network Settings screen.

[davidbaumwald]

With 5.5 Beta 1 releasing tomorrow ans this still needing a refresh and a review, 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.