feat: add configurable replicas and antiaffinity to gateway deployment for HA #1212

Job	Run time
Run Tests / Lint Code (pilot)	23s
Run Tests / Observability Integration Test (1.25-strict/stable)	37m 5s
Run Tests / Integration Test (1.27-strict/stable, integration)	44m 5s
Run Tests / Lint Code (gateway)	22s
Run Tests / Observability Integration Test (1.26-strict/stable)	36m 36s
Run Tests / Integration Test (1.27-strict/stable, integration-tls-provider)	38m 52s
Run Tests / Integration Test (1.27-strict/stable, integration-tls-secret)	34m 39s
Run Tests / Unit Test (pilot)	39s
Run Tests / Integration Test (1.30-strict/stable, integration)	41m 34s
Run Tests / Unit Test (gateway)	42s
Publish Charm / Generate the Charm Matrix	2s
Run Tests / Integration Test (1.30-strict/stable, integration-tls-provider)	38m 59s
Run Tests / Integration Test (1.30-strict/stable, integration-tls-secret)	36m 58s
Run Tests / Check libraries (istio-gateway) / Check libraries	36s
Run Tests / Check libraries (istio-gateway) / Lint	9s
Run Tests / Check libraries (istio-pilot) / Lint	9s
Run Tests / Check libraries (istio-pilot) / Check libraries	28s
Run Tests / Terraform (gateway) / Lint Terraform	7s
Run Tests / Terraform (pilot) / Lint Terraform	6s
Run Tests / Terraform (gateway) / Apply / Apply Terraform	5m 35s
Run Tests / Terraform (gateway) / Check / Check Terraform	6s
Run Tests / Terraform (pilot) / Apply / Apply Terraform	5m 15s
Run Tests / Terraform (pilot) / Check / Check Terraform	6s
Publish Charm / Publish Charm (./charms/istio-gateway)	13m 8s
Publish Charm / Publish Charm (./charms/istio-pilot)	17m 13s
	5h 53m 54s

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