EKS Cross Account Observability using central AMP (#213)

* Added example for multi-cluster eks-monitoring and made changes to eks-monitoring module to allow cross-cluster IRSA

* Updated eks-monitoring module's README to add the variable description

* Hard-coded grafana license type in eks-cross-cluster-with-amp/main.tf

* Added README page for eks-cross-account-with-central-amp

* Extracted out the eks/amg creation and modified it to use existing resources

* Update README.md to add multiaccount dashboard png

* Updated README.md and multiaccount.md to add eks multiaccount png

* Updated eks-cross-cluster-with-amp example to disable dashboard creation for cluster 2

* Pre commit changed committed

* Fixed cross-account-observability docs and README.md and added variable for amp_workpace_alias

* Removed extra spacing in multiaccount.md and added precommit suggested changes

* Modified cross-account-observability example to change cross-account-amp-role to snake_case

* Capitalized Terraform string in multiaccount.md and converted iam-role-attach to snake_case

---------

Co-authored-by: Rodrigue Koffi <bonclay7@users.noreply.github.com>

modules/eks-monitoring/variables.tf

@@ -33,6 +33,12 @@ variable "irsa_iam_permissions_boundary" {
   default     = null
 }
 
+variable "irsa_iam_additional_policies" {
+  description = "IAM additional policies for IRSA roles"
+  type        = list(string)
+  default     = []
+}
+
 variable "adot_loglevel" {
   description = "Verbosity level for ADOT collector logs. This accepts (detailed|normal|basic), see https://aws-otel.github.io/docs/components/misc-exporters for mor infos."
   type        = string
@@ -57,6 +63,12 @@ variable "managed_prometheus_workspace_region" {
   default     = null
 }
 
+variable "managed_prometheus_cross_account_role" {
+  description = "Amazon Managed Prometheus Workspace's Account Role Arn"
+  type        = string
+  default     = ""
+}
+
 variable "enable_alerting_rules" {
   description = "Enables or disables Managed Prometheus alerting rules"
   type        = bool