Add Accepted status condition to DNSPolicy

[maleck13]

What

Based on https://github.com/Kuadrant/architecture/blob/main/rfcs/0004-policy-status.md we want to have some consistent status in place.

One of those status conditions is the Ready condition which is already present in DNSPolicy.

But we want to change that to a new condition Accepted this is in affect that the controller has validated that the policy is correct and valid and ready to be acted on. Things that may cause this not to be the case

• DNSPolicy targeting a non gateway resource
• DNSPolicy targeting a resource that has been deleted or not found
• Another DNSPolicy being present and targeting the same ref

Done

• Replace the existing ready condition and add logic to validate and calculate the correct Accepted condition in the DNSPolicy controller based on the RFC
• Unify the approach so that it can be reused by TLSPolicy
• Add new tests where appropriate
• Update the DNSPolicy reference doc to call out the new status conditions https://docs.kuadrant.io/multicluster-gateway-controller/docs/dnspolicy/dns-policy/

[laurafitzgerald]

@sergioifg94 unassigning this one from myself, just fyi.

[philbrookes]

This issue is stale because it has been open for 60 days with no activity.

[KevFan]

Accepted Condition completed as part of Kuadrant/kuadrant-operator#416