API to generate DNSRecord endpoints for a given strategy and Gateway

[mikenairn]

What

Add a public API to the dns operator that generates endpoints for a given strategy (simple/loadbalanced) and Gateway. This should replace the logic currently in the kuadrant operator.

Why

• Allows the logic generating the endpoints to exist next to the code that is expected to reconcile the results.
• Allows us to more easily create test cases based on strategies

Notes

• It is not the intention that the dnsrecord controller itself will become aware of strategies. It should continue to function based on the contents of the DNSRecord.Endpoints
• Strategies will now be defined by the dns operator and not the kuadrant operator
• Do we remove ACM support which complicates things? Yes