[Frontend] Add a section in admin settings for instance-level external audit destination

What?

We need to create a section under admin settings named "Compliance" or "Audit Events". Under that we need to provide an option for listing, creating, updating and deleting the instance level external audit events destination.

Implementation details

1. This feature should be released after deployment of changes in issue #335176 (closed).
2. The APIs will be GraphQL APIs and details can be found in description of issue #335175 (closed).

Implementation plan

1. Create new FF instance_streaming_audit_events
2. First MR
   1. add FF and show tab. Add variables show_streams, group_path, empty_state_svg_path to ee/app/views/admin/audit_logs/index.html.haml for the tab to show
   2. Will need to move the export button above the tabs in ee/app/assets/javascripts/audit_events/components/audit_events_app.vue
   3. Also pass through a new boolean around that this is instance level streaming for conditionals below (Can be added in ee/app/helpers/audit_events_helper.rb)
3. Second MR
   1. Update the Apollo query to pull instance level destination instead of from group ee/app/assets/javascripts/audit_events/components/audit_events_stream.vue
   2. Update the Apollo queries to add, edit and delete instance level destination instead of from group ee/app/assets/javascripts/audit_events/components/stream/stream_destination_editor.vue
   3. We will need to hide the headers until the API is ready in fourth MR
   4. Will also need to hide filters at instance level