Rename the host key to more RFC reliant namr

[asonnleitner]

According to RFC-1738 the host is constructed from the hostname and optionally port. But in the config we are specifying the full GraphQL endpoint URL, including the path.

https://www.rfc-editor.org/rfc/rfc1738#section-3.1

Proportional
Change the host in the config to more fitting name to maybe one of:

• uri as the Apollo client https://www.apollographql.com/docs/react/get-started/#step-3-initialize-apolloclient
• endpoint
• url

Also willing to contribute