Warnings for overriding controller-managed ENV vars

[shaneutt]

Problem Statement

It's possible for end-users to override ENV variables for ControlPlane and DataPlane that are intended to only be provided by the controller, when using GatewayConfiguration. Examples include CONTROLLER_PUBLISH_SERVICE which the Gateway controller expects to manage itself. The purpose of this task is to emit warnings when this happens, so that the user can come to some sort of awareness that this may not be what they intended, or that it may have adverse effects.

Anything else ?

Generate both logs and events for this.

Acceptance Criteria

• when manually setting values in the GatewayConfiguration for fields that are not expected to be managed by end-users, warnings are emitted that help the user understand that what they're doing may have unintended side effects, as the controller intends to manage these.
• a note in docs is added about this

Notes

Extra context: previously in Kong/gateway-operator-archive#109 we actually suggested blocking these configurations outright. Technically we could still do this in the future, but the team decided that for the early alpha phase we would evaluate simply emitting warnings about this.

[github-actions]

This issue has been automatically marked as stale due to 60 days of inactivity. Please update or comment if this is still relevant.