Translate data plane UpstreamSettingsPolicy configuration into NGINX configuration

[kate-osborn]

As a user of NGF
I want the data plane configuration generated from my UpstreamSettingsPolicy to be translated into NGINX Configuration
So that the features I configured in my UpstreamSettingsPolicy take effect within NGF.

Acceptance

• The data plane configuration for UpstreamSettingsPolicies are translated into NGINX directives in the Go templates.
• When keepalives are enabled for an upstream the connection header must be empty.

[github-actions]

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