Make version data and usage pings opt-in

What does this MR do?

Swaps the default from opt-out to opt-in

Are there points in the code the reviewer needs to double check?

Much discussion in #47874 . Version ping wasn't explicitly talked about there, but I think it also needs to be opt-in by the same argument.

The interaction with the usage_ping_enabled config file setting is now a bit weird - at present, the most sensible option I saw was a tri-state boolean where nil means take the database setting, false means it cannot be enabled and true means it can be enabled, but take the database setting. This might need some work. Perhaps true should mean it is enabled regardless of the database setting, to mirror the false behaviour?

Why was this MR needed?

GDPR

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a Backend maintainer
• Conform by the merge request performance guides
• Conform by the style guides
• Conform by the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #47874