Helm-apps role for installing helm charts (#8347)

* Sketch of helm-apps role interface

* helm-apps: Early implementation and settings

* helm-apps: Fix README.md example playbook

* fixup! Sketch of helm-apps role interface

* Make the argument specs more explicit

* Remove exposed options from hardcoded default

* Simplify example playbook in README.md

- Define directly the roles parameters
- Add an example of option override for one chart only

* Use release instead of charts

Make explicit that the role is mananing releases, not charts.
Simplify parameters naming

roles/helm-apps/tasks/main.yml

@@ -0,0 +1,17 @@
+---
+- name: Add Helm repositories
+  kubernetes.core.helm_repository: "{{ helm_repository_defaults | combine(item) }}"
+  loop: "{{ repositories }}"
+
+- name: Update Helm repositories
+  kubernetes.core.helm:
+    state: absent
+    binary_path: "{{ bin_dir }}/helm"
+    release_name: dummy  # trick needed to refresh in separate step
+    release_namespace: kube-system
+    update_repo_cache: true
+  when: repositories != []
+
+- name: Install Helm Applications
+  kubernetes.core.helm: "{{ helm_defaults | combine(release_common_opts, item) }}"
+  loop: "{{ releases }}"