React client: Remove apollo-link deprecated package

[lakardion]

apollo-link packages have been deprecated by the apollo team : https://github.com/apollographql/apollo-link

Apparently they are already including the same functionalities in their v3 (which is already part of our react client)
https://www.apollographql.com/docs/react/migrating/apollo-client-3-migration/#apollo-link-

Seems like the only change required is to replace the imports to point to:

import {createHttpLink} from '@apollo/client/link/http'
import {setContext} from '@apollo/client/link/context'