Make `NB_FEDERATE_REMOTE_PUBLIC_NODES` part of the default `.ini` template - or default to FALSE

[surchs]

Most of the time when I deploy a portal, I don't want to include the public federation nodes now. If I want to turn this off, I currently need to

1. Find https://neurobagel.org/user_guide/maintaining/#environment-variables-reference
2. Find NB_FEDERATE_REMOTE_PUBLIC_NODES
3. Figure out where to put this
4. Put it in the .ini file
5. Set it to False

I'd rather that either

• NB_FEDERATE_REMOTE_PUBLIC_NODES is included in the prod .ini template for portal so I can remember it and change it (starting to break with the principle of the .ini file being as sparse as possible) OR
• NB_FEDERATE_REMOTE_PUBLIC_NODES to default to FALSE (would make fresh portal display with zero nodes)