DEV: Refactor the Automation Plugin UI to match admin UI guidelines (#31060)

This change updates the Automation plugin to make use of the `use_new_show_route` plugin flag, as well as generally updating the UI to match current admin UI guidelines. Notable changes include:

- Moving template/router/controller files to make use of the `admin.adminPlugins.show` route.
- Changing the URIs from `/admin/plugins/discourse-automation` to `/admin/plugins/automation`, to match the `PLUGIN_NAME`.
- Adding UI wrappers around the New/Edit forms, and polishing the list of defined automations.

plugins/automation/spec/system/page_objects/discourse_automation/automation.rb

@@ -4,7 +4,7 @@ module PageObjects
   module Pages
     class Automation < PageObjects::Pages::Base
       def visit(automation)
-        super("/admin/plugins/discourse-automation/#{automation.id}")
+        super("/admin/plugins/automation/automation/#{automation.id}")
         self
       end
 
@@ -34,7 +34,7 @@ module PageObjects
       end
 
       def form
-        @form ||= find(".discourse-automation-form.edit")
+        @form ||= find(".discourse-automation-edit")
       end
     end
   end

plugins/automation/spec/system/page_objects/discourse_automation/new_automation.rb

@@ -4,7 +4,7 @@ module PageObjects
   module Pages
     class NewAutomation < PageObjects::Pages::Base
       def visit
-        super("/admin/plugins/discourse-automation/new")
+        super("/admin/plugins/automation/automation/new")
         self
       end