Deprecate hiera lookup (#10779)

Deprecate hiera lookup.

changelogs/fragments/hiera.yml

@@ -0,0 +1,4 @@
+deprecated_features:
+  - "hiera lookup plugin - retrieving data with Hiera has been deprecated a long time ago; because of that this plugin will be removed from community.general 13.0.0.
+     If you disagree with this deprecation, please create an issue in the community.general repository
+     (https://github.com/ansible-collections/community.general/issues/4462, https://github.com/ansible-collections/community.general/pull/10779)."

meta/runtime.yml

@@ -119,6 +119,12 @@ plugin_routing:
       redirect: community.google.gcp_storage_file
     hashi_vault:
       redirect: community.hashi_vault.hashi_vault
+    hiera:
+      deprecation:
+        removal_version: 13.0.0
+        warning_text: >-
+          Hiera has been deprecated a long time ago.
+          If you disagree with this deprecation, please create an issue in the community.general repository.
     manifold:
       tombstone:
         removal_version: 11.0.0

plugins/lookup/hiera.py

@@ -15,6 +15,12 @@ requirements:
   - hiera (command line utility)
 description:
   - Retrieves data from an Puppetmaster node using Hiera as ENC.
+deprecated:
+  removed_in: 13.0.0
+  why: >-
+    Hiera has been deprecated a long time ago.
+    If you disagree with this deprecation, please create an issue in the community.general repository.
+  alternative: Unknown.
 options:
   _terms:
     description: