fix(federatedfilesharing): warn when enabling lookup server data upload

[susnux]

• Resolves: #

Summary

1. Switch default from true to false for user data upload to lookup server
2. Add warning when enabling the upload to make sure the admin understands what it will cause.

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)

[szaimen]

Good idea! LGTM but did not test

[ArtificialOwl]

We should have take this opportunity to switch to IAppConfig and ConfigLexicon :-)

More seriously, we should ignore value from 'lookupServerUploadEnabled' if 'lookup_server' 'gs.enabled' exists and is set (for a smooth upgrade on Global Scale)

[nickvergessen]

We should have take this opportunity to switch to IAppConfig and ConfigLexicon :-)

We can do this in a follow up.
I think the original change needs backporting a bit further than those things exist