Intentions module input configuration

[noejbrown]

Change: added new configuration for module_input "intentions" and updated necessary module input dependencies

Commits :

• Added intentions monitor configuration and test
• Added intentions services configuration for source_services and destination_services used in the "intentions" block
• Added intentions module input configuration and test
• Updated module_input.go and module_input_test.go to include the new module_input "intentions"

Sample "intentions" module_input

task {
	name = "module_input_task"
	module = "..."
	condition "schedule" {
		cron = "* * * * * * *"
	}
	module_input "intentions" {
		datacenter = "datacenter"
		namespace = "namespace"
		source_services {
			regexp = "^web.*"
		}
		destination_services {
			regexp = "^api.*"
		}
	}
}`

[noejbrown]

Did a rebase, this change does not require release engineers to review anymore. Removing you all as reviewers thanks.

[hashi-derek]

This PR looks good, but not marking it as approved yet. We will utilize this as the feature branch for all intentions work, so there will be other PRs merged into this.

[jwair]

I am not sure about the correctness of this logic
I understand that we want to specify either Names OR Regex, but that is business logic, and the struct doesn't know about this restriction. Therefore, IF I create an IntentionsServicesConfig object with both Names and Regex defined, I expect the GoString() method to return a string with both fields, not just Names.

[noejbrown]

This logic behind this is for the expected use case that both fields wouldn't be defined. If you create IntentionsServicesConfig object with both field defined, the validate function that is prior to this would fail. I could see putting an error message here instead if both are configured but showing both didn't make sense to me because the output would be :

&IntentionsModuleInputConfig{&IntentionsMonitorConfig{Datacenter:dc, Namespace:namespace, Source Services: Names: Regexp:^web.*, Destination Services: Names: Regexp:^api.*}}

Could you explain more what the use case for showing both names and regexp would be? I think it would steer people into the wrong direction that you could use both and lead to test failure.