This is a change to the `config.json` file which removes certain options
that are best not touched and changes some options to make them easier
to work with.
1. We change the default journaling mode to "wal" and remove the config
option.
2. We remove the option to set the peer connection "target", as it's not
a good idea to set this to a different value, as it affects the
network.
3. We combine seeding policy & scope, since there's no need to set the
scope when the policy is "block". In that case, we always want to
block "all" remotes. The new policy configuration has the following
schema:
{ seedingPolicy: { default: "block" | "allow", scope?: "all" | "followed" } }
The "scope" key is not used when "default" is set to "block".
4. We add an `extra` field to the node config for options that are not
recognized. We use this to warn the user.