Update Data Configuration Doc for 2.0

[mpstefan]

As a user of NGF
I want the data plane configuration doc updated for 2.0
So that I can accurately update the configuration I need after the 2.0 update.

Acceptance

• The data plane configuration doc is updated to reflect the architecture changes in 2.0:
  • Update any language pertaining to NginxProxy to mention that NginxProxy is created by default when installing NGF and is attached to the GatewayClass
  • Include that NginxProxy controls infrastructure related fields as well as nginx configuration