fix(*): let orcid use 127.0.0.1 instead of localhost

When creating orcid credentials, the process fails when trying to add localhost:4000 as the redirect url.
The solution there is to add 127.0.0.1:4000 as the redirect url.
The app however, uses localhost as its default client url (on the server's config), which makes the actual redirect fail, as orcid will complain that localhost and 127.0.0.1 do not match.

This MR alleviates that by changing the default value in the config.
This means that devs can now create credentials for themselves instead of needing to pass around credentials between them.
I also updated the FAQ for clarity.

Please note that if older credentials use localhost, either the value in orcid's sandbox needs to be updated, or CLIENT_HOST=localhost needs to be explicitly passed to the server container.