Need the ability to serve on multiple paths

[BrynCooke]

Some users have clients that are using combinations of / and /graphql. Changing these clients isn't an option, so it'd be helpful you could specify multiple paths to listen on.

Suggest that we pull this stuff out of supergraph into a server section:

server:
  listen:
  paths:
    - /
    - /graphql

[o0Ignition0o]

Note this has implications around the way we validate web endpoints, and the way we set up routes in the axum router.

[smyrick]

Could also help solve: https://github.com/apollographql/router/issues/4836