feat(appconfig): Automatically store "sensitive" appconfigs encrypted in the database

[nickvergessen]

• Based on improve index on appconfig #42903

Summary

Quite some app configs contain sensitive information that we could prevent to leak, when a backup of the DB is leaked, to reduce the risk of follow up leaks/hacks.
The state of the art is to use ICrypto::encrypt() and ICrypto::decrypt() for that. While looking into it for some of the talk configs which are arrays, I thought it's a shame that we would loose all the typing as we have to json_encode the config making it strings, in order to be able to encrypt them.

So why not just encrypt all sensitive configs all the time automatically?

TODO

• Adjust normal getter and setter
• Check getAllValues and getDetails

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)