Support configurable health probes for service

[doshitan]

Context

At the moment, no special container-level probes are configured, and so services just use the Azure defaults. And at the application gateway level, just checks /health endpoint for standard success status:

template-infra-azure/infra/modules/service/application_gateway.tf

Lines 150 to 162 in 07bba4c

	probe {
	name = local.backend_probe_name
	host = local.backend_host_name
	interval = 60 # seconds
	protocol = "Https"
	path = "/health"
	timeout = 30 # seconds
	unhealthy_threshold = 5
	match {
	status_code = ["200-299"]
	}
	}

Related to navapbc/template-infra#1025

Instructions

It depends a bit on sequencing, if navapbc/template-infra#1025 has been done on the AWS side, then generally match the level of configurability there.

If not, implement basic support for setting the health probe(s) path(s) to /health (or configurable endpoint(s)). And update navapbc/template-infra#1025 to cover Azure template as well.

Success criteria

• Similar levels of support for configuration exist in Azure as in AWS

References

• https://learn.microsoft.com/en-us/azure/container-apps/health-probes

Acceptance criteria

Tech Spec - https://docs.google.com/document/d/1aKQDlg7ljUV6erIjSnZsvx-zasVajSMsJ2LKmd9HCMU/edit?usp=sharing