[azure-application] Stop storing client secrets in the state

[jalvarezit]

Description

At the moment there is no possibility to not storing client secrets in the terraform state, currently blocked from this provider issue.

Once is solved from the provider we have to use an ephemeral resource to store the secret in the key vault as well:

tfm/modules/azure-application/main.tf

Lines 89 to 95 in e4fb6ef

	resource "azurerm_key_vault_secret" "this" {
	count = (var.client_secret.keyvault != null && var.client_secret.enabled) ? 1 : 0
	key_vault_id = var.client_secret.keyvault.id
	name = var.client_secret.keyvault.key_name
	value = azuread_application_password.this[0].value
	}

Tasks

• Use ephemeral resources in both azuread_application_password and azurerm_key_vault_secret
• Validate secret rotation keeps working as intended