Add cleanup of disabled consul watcher files

What does this MR do?

Add cleanup of disabled consul watcher files
    
After disabling/renaming/removing a consul service
its watcher and configuration files were not
cleaned up.
    
An example of this problem arises during upgrades
of Patroni clusters.
    
Changelog: fixed

Related issues

Closes #7293 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
  • MR to remove rm note in the docs: Remove workaround from PostgreSQL replication docs (gitlab!114592 - merged)
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened

files/gitlab-cookbooks/consul/libraries/watch_helper.rb

@@ -72,5 +72,17 @@ module WatchHelper
     def watchers
       @all_watchers.select { |watcher| @enabled_watchers.include? watcher.name }
     end
+
+    def excess_configs
+      enabled_configs = watchers.map { |w| File.basename w.consul_config_file }
+      Dir.glob("#{@consul_config_directory}/*")
+        .reject { |c| enabled_configs.include? c }
+    end
+
+    def excess_handler_scripts
+      enabled_handlers = watchers.map { |w| File.basename w.handler_script }
+      Dir.glob("#{@handler_directory}/*")
+        .reject { |h| enabled_handlers.include? h }
+    end
   end
 end