Create new rake task with Advanced Search integration details

What does this MR do and why?

This MR adds a new rake task called gitlab:elastic:info that outputs debugging information for the Advanced Search integration.

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Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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Related to #340437 (closed)

ee/spec/tasks/gitlab/elastic_rake_spec.rb

@@ -426,38 +426,5 @@
         /Started:\s+yes\s+Halted:\s+no\s+Failed:\s+no\s+Current state:\s+{"test":"value"}/
       ).to_stdout
     end
-
-    xit 'outputs' do
-      expected = <<~END
-
-      Advanced Search
-      Server version:         7.17.0
-      Server distribution:    elasticsearch
-      Indexing enabled:       yes
-      Search enabled:         yes
-      Pause indexing:         no
-      Max size indexed:       1024 KiB
-
-      Indexing Queues Sizes
-      Initial queue:          0
-      Incremental queue:      0
-
-      Indices
-      - gitlab-test-20220628-1536:
-        number_of_shards: 5
-        number_of_replicas: 0
-      - gitlab-test-issues-20220628-1236:
-        number_of_shards: 5
-        number_of_replicas: 1
-      - gitlab-test-notes-20220628-1236:
-        number_of_shards: 5
-        number_of_replicas: 1
-      - gitlab-test-merge_requests-20220628-1236:
-        number_of_shards: 5
-        number_of_replicas: 1
-      END
-
-      expect { subject }.to output(expected).to_stdout
-    end
   end
 end